SP-3-0005

PREFACE

This document, TIA-968-A,

Telecommunications – Telephone Terminal Equipment – Technical

Requirements for Connection of Terminal Equipment to the Telephone Network,

has been

established pursuant to the Federal Communication Commission’s (“FCC”) Report and Order in
the 2000 Biennial Review of Part 68 of the Commission’s Rules and Regulations, CC Docket No.
99-216, FCC 00-400, adopted November 9, 2000 and released December 21, 2000 (“Order” or
“R&O”). The Order privatized the process by which technical criteria for the prevention of harm
are established for customer premises or terminal equipment that may be sold for connection to
the telephone network, and for the approval of such equipment to demonstrate compliance with
the relevant technical criteria. The Order directed the industry to establish the Administrative
Council on Terminal Attachments (“ACTA”) as the balanced and open body that would assume
the Commission’s Part 68 role for those items privatized in the Order (Section 68.602). This
document was created for submission to ACTA by the TIA Subcommittee TR-41.9, Technical
Regulatory Considerations. It is intended to fulfill the FCC’s requirement to establish technical
criteria for Telephone Terminal Equipment labeling requirements for Part 68 of Title 47 of the
Code of Federal Regulations.

Notice of Disclaimer and Limitation of Liability

THE INFORMATION PROVIDED IN THIS DOCUMENT IS PROVIDED “AS IS” AND “AS
AVAILABLE.” SUCH INFORMATION IS DIRECTED SOLELY TO PROFESSIONALS WHO
HAVE THE APPROPRIATE DEGREE OF EXPERIENCE TO UNDERSTAND AND INTERPRET
ITS CONTENTS, AND ANY AND ALL USE OF OR RELIANCE UPON THIS INFORMATION IS
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LIMITATION, ANY AND ALL WARRANTIES CONCERNING THE ACCURACY OF THE
INFORMATION, ITS FITNESS OR APPROPRIATENESS FOR A PARTICULAR PURPOSE OR
USE, ITS MERCHANTABILITY AND ITS NON-INFRINGEMENT OF ANY THIRD PARTY’S
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AND SPONSORS, EXPRESSLY DISCLAIMS ANY AND ALL RESPONSIBILITIES FOR THE
ACCURACY OF THE INFORMATION AND MAKES NO REPRESENTATIONS OR
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OR GROSSLY NEGLIGENT ACTS. THE FOREGOING NEGATION OF DAMAGES IS A
FUNDAMENTAL ELEMENT OF THE USE OF THE INFORMATION AND DATA CONTAINED
HEREIN, AND THIS INFORMATION WOULD NOT BE PUBLISHED BY ACTA WITHOUT SUCH
LIMITATIONS.

NOTICE

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eliminating misunderstandings between manufacturers and purchasers, facilitating
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This Standard does not purport to address all safety problems associated with its use or all
applicable regulatory requirements. It is the responsibility of the user of this Standard to
establish appropriate safety and health practices and to determine the applicability of regulatory
limitations before its use.

(From Standards Proposal No. 3-0016-URV, formulated under the cognizance of the TIA TR-41.9
Subcommittee on Technical Regulatory Considerations.)

Published by



TELECOMMUNICATIONS INDUSTRY ASSOCIATION 2002

Standards and Technology Department

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TIA-968-A

FOREWORD

(This foreword is not part of this Standard.)

The Federal Communications Commission (FCC), in its Report & Order, FCC 00-400, on
CC Docket No. 99-216, mandated creation of the Administrative Council for Terminal
Attachments (ACTA). In 47 CFR 68.7(b) ACTA was charged to adopt and publish technical
criteria to prevent harms to the telephone network submitted to it by standards development
organizations accredited by the American National Standards Institute (ANSI).

The first version of this document was an interim standard (IS) whose contents were
identical to the criteria in Part 68 of Title 47 of the Code of Federal Regulations at the time
the Report & Order was issued. One objective of this updated version is to advance the
document from an IS to an ANSI approved standard. Additionally, the following changes
have been made in this version:
1) The encoded analog content requirement for V.90 and V.92 modems has been relaxed.
2) Requirements for stutter dial tone detection devices previously in TIA/EIA-IS-883 have

been incorporated.

3) Requirements for ADSL modems previously in TIA/EIA-IS-883 have been incorporated

and revised.

4) Out-of-band metallic voltage limits for analog voice-band and Local Area Data Channel

(LADC) TE have been extended from 6 MHz to 30 MHz.

5) Transverse balance requirements for ADSL modems and other TE have been clarified.
6) Connector wiring configurations have been removed and T1.TR.5-1999 is now

referenced.

7) Alternative frequency domain signal power limits have been added for digital sub-rate

TE.

8)  The encoded analog content requirement has been extended to other applicable TE .
9)  Minor editorial corrections and clarifications.

The standard was produced by Working Group TR-41.9.1 of Subcommittee TR-41.9,
Technical Regulatory Considerations. It was developed in accordance with ANSI and
TIA/EIA procedural guidelines and represents the consensus position of the Working Group
and its parent Subcommittee, which served as the formulating group. It has also received
the concurrence of Engineering Committee TR-41, User Premises Telecommunications
Requirements. Committee approval of this standard does not necessarily imply that all
members voted for its approval.

TIA-968-A

Working Group TR-41.9.1 acknowledges the contribution made by the following individuals
in the development of this version of this Standard.

Name Representing

Larry Bell

ADTRAN, Inc.

Trone T Bishop, Jr

Verizon Communications

Cliff Chamney

Sprint

Phillip Havens

Teccor Electronics

Tim Lawler

Cisco Systems

Henry Mar

Industry Canada

Anh Nguyen

Underwriters Laboratories

Clint Pinkham

ATLINKS USA Inc.

Scott Roleson

Hewlett-Packard Company

John Shinn

Sanmina Homologation Service

Greg Slingerland

Mitel Networks

Tailey Tung

Siemens

Peter Walsh

Paradyne Corporation

Stephen R Whitesell

VTech

Suggestions for improvement of this Standard are welcome. They should be sent to:

Telecommunications Industry Association

Engineering Department

Suite 300

2500 Wilson Boulevard

Arlington, VA 22201

vii

TIA-968-A

1 GENERAL

1.1 SCOPE

This standard specifies technical criteria for terminal equipment approved in accordance
with 47 CFR 68 for direct connection to the public switched telephone network, including
private line services provided over wireline facilities owned by providers of wireline
telecommunications. These technical criteria are intended to protect the telephone network
from the harms defined in 47 CFR 68.3. Conformance to the technical criteria in this
standard will not assure compatibility with wireline carrier services.

Except for the grandfathered terminal equipment identified in Annex A, the technical criteria
in this standard apply to the direct connection:

a) Of all terminal equipment to the public switched telephone network, for use

in conjunction with all analog services other than party line service;

b) Of all terminal equipment to channels furnished in connection with foreign

exchange lines (customer-premises end), the station end of off-premises
stations associated with PBX and Centrex services, trunk-to-station tie lines
(trunk end only) and switched service network station lines (CCSA and
EPSCS);

c) Of all PBX (or similar) systems to private line services for tie trunk type

interfaces and off premises station lines;

d) Of all terminal equipment to subrate and 1.544 Mbps digital services;
e) Of approved terminal equipment or approved protective circuitry to Local

Area Data Channels and to channels which are similar to Local Area Data
Channels that are obtained as special assemblies;

f) Of all terminal equipment or systems to voiceband private line channels for

2-point and multipoint private line services (excluding those identified in
Category II, AT&T Tariff F.C.C. No. 260 or subsequent revisions) that utilize
loop start, ringdown or inband signaling; or voiceband metallic channels;

g) Of the types of test equipment specified in section 1.3.56;

Of all terminal equipment to Public Switched Digital Service (PSDS) Type I,
II,or III;

i) Of all terminal equipment to the Integrated Services Digital Network (ISDN)

Basic Rate Access (BRA) or Primary Rate Access (PRA).

j) Of all terminal equipment to ADSL services

These criteria apply to terminal equipment approved after publication of this document.
Previously approved TE retains its status under the requirements in effect at the time the TE
was approved. All TE shall continue to comply with the requirements in effect when the TE
was approved. Equipment grandfathered by FCC action is identified in Annex A along with
the conditions that allow such TE to be connected without approval.

` TIA-968-A

TE that is modified shall be re-approved under the requirements in effect at the time of the
modification, not necessarily those requirements in effect at the time of the prior approval.
Except as other wise specified herein, A modification is any change that affects the
compliance of TE to this standard. Repair to TE, where no modification has occurred, does
not require re-approval.

Requirements retained by the Commission in 47 CFR Part 68, including hearing aid
compatibility and volume control, are not covered in this standard.

Two categories of specifications are used in this standard, mandatory requirements and
recommendations. Mandatory requirements are designated by the word "shall" and
recommendations by the word "should".

1.2 NORMATIVE REFERENCES

The following standard contains provisions which, through reference in this text, constitute
provisions of this Standard. At the time of publication, the editions indicated were valid. All
standards are subject to revision, and parties to agreements based on this Standard are
encouraged to investigate the possibility of applying the most recent editions of the
standards indicated below. ANSI and TIA maintain registers of currently valid national
standards published by them. Informative references are provided in Annex B.

1) 47 CFR Part 68, Code of Federal Regulations (CFR), Title 47, FCC Part 68,

Connection of Terminal Equipment to the Telephone Network.

2) ITU-T Recommendation G.711, 1993,

General Aspects of Digital Transmission

Systems - Terminal Equipment - Pulse Code Modulation (PCM) of Voice
Frequencies.

TIA/EIA TSB 31-B, Part 68 Rationale and Measurement Guidelines.

1.3 DEFINITIONS

For the purposes of this Standard, the following definitions apply:

NOTE:

Informative definitions are included in Annex B.

TIA-968-A

1.3.1

Approved protective circuitry:

Separate, identifiable and discrete electrical circuitry

designed to protect the telephone network from harm, which is approved in
accordance with the rules and regulations in 68.7(b) and Subpart C of 47 CFR Part
68.

1.3.2

Approved terminal equipment:

Terminal equipment that is approved in accordance

with the rules and regulations in 68.7(b) and Subpart C of 47 CFR Part 68.

1.3.3

Asymmetric Digital Subscriber Line (ADSL) Modem:

A modem having transmit

signal characteristics meeting the spectral response and aggregate power level
limitations of this

standard.

The term should be interpreted to include variations such

as splitterless ADSL and Rate Adaptive DSL (RADSL) modems that have similar
transmit signal characteristics meeting these limitations.

1.3.4

Auxiliary leads:

Terminal equipment leads at the interface, other than telephone

connections and leads otherwise defined in this Standard, which leads are to be
connected either to common equipment or to circuits extending to central office
equipment.

1.3.5

Capture level:

Equipment with AGC (Automatic Gain Control) signal power limiting

has virtually no output signal for input levels below a certain value. At some input
signal power, the output level will become significant (usually corresponding to the
expected output level) for the service application. The input level at which this occurs
is defined as the ‘‘capture level.’’

1.3.6

Central-office implemented telephone:

A telephone executing coin acceptance

requiring coin service signaling from the central office.

1.3.7

Channel equipment:

Equipment in the private line channel of the telephone network

that furnishes telephone tip and ring, telephone tip-1 and ring-1, and other auxiliary
or supervisory signaling leads for connection at the private line channel interface
(where tip-1 and ring-1 is the receive pair for 4-wire telephone connections).

1.3.8

Coin-implemented telephone:

A telephone containing all circuitry required to

execute coin acceptance and related functions within the instrument itself and not
requiring coin service signaling from the central office.

1.3.9

Coin service:

Central office implemented coin telephone service.

1.3.10

Companion terminal equipment:

Companion terminal equipment represents the

terminal equipment that would be connected at the far end of a network facility and
provides the range of operating conditions that the terminal equipment that is being
approved would normally encounter.

1.3.11

Continuity leads:

Terminal equipment continuity leads at the network interface

designated CY1 and CY2 which are connected to a strap in a series jack
configuration for the purpose of determining whether the plug associated with the
terminal equipment is connected to the interface jack.

` TIA-968-A

1.3.12

Digital milliwatt:

A digital signal that is the coded representation of a 0 dBm, 1000

Hz sine wave.

1.3.13

Direct connection:

Connection of terminal equipment to the telephone network by

means other than acoustic and/or inductive coupling.

1.3.14

Dual Tone Multi Frequency (DTMF):

network control signaling is a method of

signaling using the voice transmission path. The method employs 16 distinct signals
each composed of two voice band frequencies, one from each of two geometrically
spaced groups designated ‘‘low group’’ and ‘‘high group.’’ The selected spacing
assures that no two frequencies of any group combination are harmonically related.

1.3.15

E&M leads:

Terminal equipment leads at the interface, other than telephone

connections and auxiliary leads, which are to be connected to channel equipment
solely for the purpose of transferring supervisory signals conventionally known as
Types I and II E&M and schematically shown in Figures 1.5 and 1.6.

1.3.16

Encoded analog content:

The analog signal contained in coded form within a data

bit stream.

1.3.17

Equivalent power:

The power of the analog signal at the output of a zero level

decoder, obtained when a digital signal is the input to the decoder.

1.3.18

Grandfathered terminal equipment:

Terminal equipment of a type allowed to be

directly connected to the telephone network under the provisions of 47 CFR Part 68
before the effective date of this standard.

1.3.19

Inband signaling private line interface:

The point of connection between an

inband signaling voiceband private line and terminal equipment or systems where
the signaling frequencies are within the voiceband. All tip and ring leads shall be
treated as telephone connections for the purposes of fulfilling approval conditions.

1.3.20

Instrument-implemented telephone:

A telephone containing all circuitry required to

execute coin acceptance and related functions within the instrument itself and not
requiring coin service signaling from the central office.

1.3.21

ISDN basic rate interface:

A two-wire interface between the terminal equipment and

ISDN BRA. The tip and ring leads shall be treated as telephone connections for the
purpose of fulfilling approval conditions.

1.3.22

ISDN Primary Rate Interface:

A four-wire interface between the terminal equipment

and 1.544 Mbps ISDN PRA. The tip, ring, tip-1, and ring-1 leads shall be treated as
telephone connections for the purpose of fulfilling approval conditions.

1.3.23

Local area data channel (LADC) leads:

Terminal equipment leads at the interface

used to transmit and/or receive signals which may require greater than voiceband
frequency spectrum over private line metallic channels designated Local Area Data
Channels (LADC). These leads shall be treated as ‘‘telephone connections’’ as
defined in this section or as tip and ring connections where the term ‘‘telephone

TIA-968-A

connection’’ is not used.

1.3.24

Local area data channel simulator circuit:

A circuit for connection in lieu of a Local

Area Data Channel to provide the appropriate impedance for signal power tests. The
schematic of Figure 1.10 is illustrative of the type of circuit that shall be used over the
given frequency ranges. When used, the simulator shall be operated over the
appropriate range of loop resistance for the equipment under test, under all voltages
and polarities that the terminal under test and a connected companion unit are
capable of providing.

1.3.25

Longitudinal voltage:

One half of the vector sum of the potential difference

between the tip connection and earth ground, and the ring connection and earth
ground for the tip, ring pair of 2- wire and 4-wire connections; and, additionally for 4-
wire telephone connections, one half of the vector sum of the potential difference
between the tip-1 connection and earth ground and the ring-1 connection and earth
ground for the tip-1, ring-1 pair (where tip-1 and ring-1 are the receive pair).

1.3.26

Loop simulator circuit:

A circuit that simulates the network side of a 2-wire or 4-

wire telephone connection during testing. The required circuit schematics are shown
in Figure 1.1 for 2-wire loop or ground start circuits, Figure 1.2 for 2-wire reverse
battery circuits, Figure 1.3 for 4-wire loop or ground start circuits, Figure 1.4 for 4-
wire reverse battery circuits, and Figure 1.9 for voiceband metallic channels. Figure
1.8 is an alternative termination for use in the 2-wire loop simulator circuits. Other
implementations may be used provided that the same dc voltage and current
characteristics and ac impedance characteristics will be presented to the equipment
under test as are presented in the illustrative schematic diagrams. When used, the
simulator shall be operated over the entire range of loop resistance as indicated in
the Figures, and with the indicated polarities and voltage limits. Whenever loop
current is changed, sufficient time shall be allocated for the current to reach a
steady-state condition before continuing testing.

1.3.27

Make-busy leads:

Terminal equipment leads at the network interface designated

MB and MB1. The MB lead shall be connected by the terminal equipment to the MB1
lead when the corresponding telephone line is to be placed in an unavailable or
artificially busy condition.

1.3.28

Metallic Voltage:

The potential difference between the tip and ring connections for

the tip, ring pair of 2-wire and 4-wire connections and additionally for 4-wire
telephone connections, between the tip-1 and ring-1 connections for the tip-1, ring-1
pair (where tip-1 and ring-1 are the receive pair).

1.3.29

Multi-port equipment:

Equipment that has more than one telephone connection

with provisions internal to the equipment for establishing transmission paths among
two or more telephone connections.

1.3.30

Network port:

An equipment port of approved protective circuitry which port faces

the telephone network.

1.3.31

Off-premises line simulator circuit:

A load impedance for connection, in lieu of an

` TIA-968-A

off-premises station line, to PBX (or similar) telephone system loop start circuits
(Figure 1.7) during testing. The schematic diagram of Figure 1.7 is illustrative of the
type of circuit which shall be used; alternative implementations may be used
provided that the same dc voltage and current characteristics and ac impedance
characteristics of Figure 1.7 shall be presented to the equipment under test as are
presented in the illustrative schematic diagram. When used, the simulator shall be
operated over the entire range of loop resistances as indicated in Figure 1.7, and
with the indicated polarities. Whenever loop current is changed, sufficient time shall
be allocated for the current to reach a steady-state condition before continuing
testing.

1.3.32

Off-premises station interface:

The point of connection between PBX telephone

systems (or similar systems) and telephone company private line communication
facilities used to access approved station equipment located off the premises.
Equipment leads at this interface are limited to telephone tip and ring leads
(designated T(OPS) and R(OPS)) where the PBX employs loop-start signaling at the
interface. Unless otherwise noted, all T(OPS) and R(OPS) leads shall be treated as
telephone connections for purposes of fulfilling approval conditions.

1.3.33

One-port equipment:

Equipment that has either exactly one telephone connection,

or a multiplicity of telephone connections arranged so that no transmission occurs
among such telephone connections, within the equipment.

1.3.34

Overload Point:

For signal power limiting circuits incorporating automatic gain

control method, the “overload point” is the value of the input signal that is 15 dB
greater than the capture level. For signal power limiting circuits incorporating peak
limiting method, the ”overload point” is defined as the input level at which the
equipment’s through gain decreases by 0.4 dB from its nominal constant gain.

1.3.35

Power connections:

The connections between commercial power and any

transformer, power supply rectifier, converter or other circuitry associated with
approved terminal equipment or approved protective circuitry. The following are not
power connections. (a) Connections between approved terminal equipment or
approved protective circuitry and sources of non-hazardous voltages (see section
4.4.4.4 for a definition of non-hazardous voltages). (b) Conductors that distribute any
power within approved terminal equipment or within approved protective circuitry. (c)
Green wire ground (the grounded conductor of a commercial power circuit that is UL-
identified by a continuous green color).

1.3.36

Private line channel:

Telephone company dedicated facilities and channel

equipment used in furnishing private line service from the telephone network for the
exclusive use of a particular party or parties.

1.3.37

PSDS Type II Analog Mode Loop Simulator Circuit:

A circuit simulating the

network side of the two-wire telephone connection that is used for testing terminal
equipment to be connected to the PSDS Type II loops. Figure 1.12

shows the type

of circuit that shall be used. Other test circuit configurations may be used provided
they operate at the same DC voltage and current characteristics and AC impedance
characteristics presented in the illustrated circuit. When utilized, the simulator should
be operated over the entire range of loop resistances, and with the indicated voltage

TIA-968-A

limits and polarities. Whenever the loop current is changed, sufficient time shall be
allowed for the current to reach a steady-state condition before continuing testing.

1.3.38

Public Switched Digital Service Type I (PSDS Type I):

This service functions only

in a digital mode. It employs a transmission rate of 56 kbps on both the transmit and
receive pairs to provide a four-wire full duplex digital channel. Signaling is
accomplished using bipolar patterns that include bipolar violations.

1.3.39

Public Switched Digital Service Type II (PSDS Type II):

This service functions in

two modes, analog and digital. Analog signaling procedures are used to perform
supervisory and address signaling over the network. After an end-to-end connection
is established, the switched Circuit Data Service Unit SCDSU) is switched to the
digital mode. The time compression multiplexing (TCM) transmission operated at a
digital transmission speed of 144 kbps to provide full-duplex 56 kbps on the two-wire
access line.

1.3.40

Public Switched Digital Service Type III (PSDS Type III):

This service functions

only in a digital mode. It uses a time compression multiplexing (TCM) rate of 160
kbps, over one pair, to provide two full-duplex channels – an 8 kbps signaling
channel for supervisory and address signaling, and a 64 kbps user data channel on a
two-wire access line.

1.3.41

Ringdown private line interface:

The point of connection between ringdown

voiceband private line service and terminal equipment or systems that provide
ringing (20 or 30 Hz) in either direction for alerting only. All tip and ring leads shall be
treated as telephone connections for the purposes of fulfilling approval conditions.
On 2-wire circuits the ringing voltage is applied to the ring conductor with the tip
conductor grounded. On 4-wire circuits the ringing voltage is simplexed on the tip
and ring conductors with ground simplexed on the tip-1 and ring-1 conductors.

1.3.42

Specialty adapters:

Adapters that contain passive components such as resistive

pads or bias resistors typically used for connecting data equipment having fixed-loss
loop or programmed data jack network connections to key systems or PBXs.

1.3.43

Stutter dial tone:

Interrupted dial tone. Typically, the cadence is 0.1 s on, 0.1 s off

and the interruptions are only for the first few seconds of dial tone. Stutter dial tone is
used to provide an audible signal to the equipment user in support of certain network
features.

1.3.44

Stutter dial tone detection device:

Terminal equipment that is designed to

automatically go off-hook and determine the presence or absence of stutter dial tone.

1.3.45

Sub-rate digital service:

A digital service providing for the full-time simultaneous

two-way transmission of digital signals at synchronous speeds of 2.4, 4.8, 9.6 or 56
kbps.

1.3.46

Switched Circuit Data Service Unit (SCDSU):

A CPE device, with PSDS

functionality, located between the Network Interface and the data terminal
equipment. (It also is sometimes referred to as Network Channel Terminating

` TIA-968-A

Equipment).

1.3.47

Telephone Connection:

Connection to telephone network tip and ring leads for 2-

wire and 4-wire connections and, additionally, for 4-wire telephone connections, tip-1
and ring-1 leads and all connections derived from these leads. The term ‘‘derived’’ as
used here means that the connections are not separated from telephone tip and ring
or from telephone tip-1 and ring-1 by a sufficiently protective barrier. Provisions of
this Standard that apply specifically to telephone network tip and ring pairs shall also
apply to telephone network tip-1 and ring-1 pairs unless otherwise specified. In 4-
wire connections, leads designated tip and ring at the interface are for transmitting
voice frequencies toward the network and leads designated tip-1 and ring-1 at the
interface are for receiving voice frequencies from the network.

1.3.48

Telephone Network:

The public switched network and those private lines which are

defined in section 1.1 of this standard.

1.3.49

Terminal Equipment (TE):

Communications equipment located on customer

premises at the end of a communications link, that is used to permit the stations
involved to accomplish the provision of telecommunications or information services

1.3.50

Terminal Port:

An equipment Port of approved protective circuitry which port faces

remotely-located terminal equipment.

1.3.51

Test Equipment:

Equipment connected at the customer’s premises that is used on

the customer’s side of the network interfaces to measure characteristics of the
telephone network, or to detect and isolate a communications fault between a
terminal equipment entity and the telephone network. Approval is required for test
equipment capable of functioning as portable traffic recorded or equipment capable
of transmitting or receiving test tones; except approval is not required for devices
used by telephone companies solely for network installation and maintenance
activities such as hand-held data terminals, linesmen’s handsets, and subscriber line
diagnostic devices.

1.3.52

Tie trunk transmission interfaces:

2-Wire:

A 2-wire transmission interface with a path that is essentially

lossless (except for 2-dB switched pad operation, or equivalent) between
the interface and the 2-wire or 4-wire, transmission reference point of the
terminal equipment.

4-Wire lossless:

A 4-wire transmission interface with a path that is

essentially lossless (except for 2 dB switched pad operation, or equivalent)
between the interface and the 2-wire or 4-wire transmission reference point
of the terminal equipment; and

Direct Digital Interface:

An interface between a digital PBX and a digital

transmission facility.

Digital Tandem 4-Wire Interface:

A 4-wire digital interface between digital

terminal equipment and a digital transmission facility operating at 1.544
Mbps or sub-rate connecting terminal equipment that provide tandem
connections.

TIA-968-A

Digital Satellite 4-wire Interface:

A 4-wire digital interface between digital

terminal equipment and a digital transmission facility operating at 1.544
Mbps or sub-rate connecting terminal equipment that does not provide
tandem connections to other digital terminal equipment.

1.3.53

Voiceband:

For the purpose of this standard, the voiceband for analog interfaces is

the frequency band from 200 Hz to 3995 Hz.

1.3.54

Voiceband metallic private line channel interface:

The point of connection

between a voiceband metallic private line channel and terminal equipment or
systems where the network does not provide any signaling or transmission
enhancement. Approved terminal equipment or systems may use convenient
signaling methods so long as the signals are provided in such a manner that they
cannot interfere with adjacent network channels. All tip and ring leads shall be
treated as telephone connections for the purpose of fulfilling approval conditions.

1.3.55

Zero Level Decoder:

The zero level de-coder shall comply with the µ = 255 PCM

encoding law as specified in ITU–T G.711 for voiceband encoding and decoding.
See also Figure 1.11

1.3.56

1.544 Mbps digital CO 4-wire interface:

A 4-wire digital interface between digital

terminal equipment and a digital transmission facility operating at 1.544 Mbps
connecting to a serving central office.

1.3.57

1.544 Mbps digital service:

A full-time dedicated private line circuit used for the

transmission of digital signals at a speed of 1.544 Mbps.

` TIA-968-A

= 500 µF – 10% + 50%

= 600

Ω

Condition V

(V)

Switch Position

For Test

+ R

Min 42.5

Max 56.5

Both

Continuously variable over

400 to 1740

Ω

2 105 2

2000

Ω

NOTES:

1. Means shall be used to generate, at the point of tip and ring connections to the

terminal equipment or protective circuitry, the parameters of dc line current and ac
impedance that are generated by the illustrative circuit depicted above (as
appropriate for the equipment under test).

2. In the Transverse Balance Limitation section 4.6, the use of the "dc portion of the

loop simulator circuit" is specified. In such case components of R

and C

shall be

removed.

3. Tests for compliance shall be made with either R

= 600

Ω

or R

replaced by the

alternative configuration shown in Figure 1.8.

Figure 1.1 2-Wire Loop Simulator for Loop Start and Ground Start Circuits

TIA-968-A

= 500 µF – 10% + 50%

= 600

Ω

+ R

Continuously variable over 400 to 2450

Ω

NOTE:

The notes for Figure 1.1 also apply to this Figure.

Figure 1.2 Loop Simulator for Reverse Battery Circuits

` TIA-968-A

SW = Polarity Switch
L

= L

> 5 H (Resistance = R

, R

)

= R3 = 600

Ω

= C

= 500 µF – 10% + 50%

Condition V

(Volts)

Switch Position

For Test

+ R

Min = 42.6

Max = 56.5

Both

Continuously

Variable over

400 to 1740

Ω

2 105 2

2000

Ω

Figure 1.3 Loop Simulator Circuit for 4-Wire Loop Start and Ground Start

TIA-968-A

= L

> 5 H (Resistance = R

, R

)

= R

= 600

Ω

= C

= 500 µF – 10% + 50%

+ R

Continuously variable over 400 to 2450

Ω

Figure 1.4 Loop Simulator Circuit for 4-Wire Reverse Battery Circuits

` TIA-968-A

+ R

continuously variable

over the following range

Condition

Switch

Position
For Test

Class A

Class B

Class C

1 1

Up to 200

Ω

Up to 800

Ω

Up to 1800

Ω

2 2 N.A.

200 to 2300

Ω

900 to 3300

Ω

The minimum current for all resistance ranges shall be 16 mA.

NOTES:

1. Means shall be used to generate, at the point of tip (T OPS) and ring (R OPS)

connections to the PBX, the range of resistance and impedance that are employed
by the illustrative circuit depicted above.

2. In the Transverse Balance Limitation section 4.6 the use of the dc portion of the loop

simulator is specified. In such cases, R

and C

shall be removed.

3. Tests for compliance shall be made with either R

= 600

Ω

or replaced by the

alternative termination specified in Figure 1.8.

Figure 1.7 Off Premises Loop Simulator

` TIA-968-A

= 500 µF – 10% + 50%

= 600

Ω

L = 10 H, Resistance = R

+ R

are continuously variable from R

to R

;

Where R

= Signaling range of Equipment Under Test, and

<< R

NOTE:

For transverse balance measurements (section 4.6), the dc portion of the loop
simulator shall be provided by removing R

and C

. Companion terminal

equipment grounds (including power supplies) shall be isolated from transverse
balance circuit grounds.

Figure 1.9 Loop Simulator Circuit – Voiceband Metallic Channels

TIA-968-A

Resistances (

Ω

), Capacitances (µF), Tolerances (

2%)

+ R

= 50 thru 3000

Ω

is the magnitude of the lowpass filter impedance that is (25

Ω

dc) 3 k

Ω

from 10 Hz to 6 kHz.
R

/2 = dc resistance of lowpass filter, Z

in parallel with 428.7

Ω

Figure 1.10 LADC Impedance Simulator for Metallic Voltage Tests

TIA-968-A

≥

10 H (Resistance = R

)

= 600

Ω

= 500 µF, - 10%, + 50%

Test Conditions for Analog Mode

V (Volts)

+ R

(

Ω

)

Min Max

Continuously

Variable

610 to 1510

Figure 1.12 Simulator Circuit for PSDS Type II in Analog Mode

TIA-968-A

4 TECHNICAL REQUIREMENTS

4.1 LABELING

The labeling of Terminal Equipment shall follow the requirements prescribed by the
Administrative Council on Terminal Attachment (ACTA).

4.2 ENVIRONMENTAL SIMULATION

Unpackaged Approved Terminal Equipment and Approved Protective Circuitry shall comply
with all the criteria specified in this standard, both prior to and after application of the
mechanical and electrical stresses specified in this section 4.2, notwithstanding that certain
of these stresses may result in partial or total destruction of the equipment. Both telephone
line surges, Type A and Type B, shall be applied as specified in sections 4.2.2 and 4.2.3.
Different failure criteria apply for each surge type.

4.2.1 Mechanical

Shock

4.2.1.1 Hand-Held Items Normally Used at Head Height: 18 random drops from a height of

1.5 meters onto concrete covered with 3 mm asphalt tile or similar surface.

4.2.1.2 Table (Desk) - Top Equipment 0–5 kg: Six random drops from a height of 750 mm

onto concrete covered with 3 mm asphalt tile or similar surface.

4.2.1.3 The drop tests specified in section 4.2.1 shall be performed as follows: The unit

shall be positioned prior to release to ensure as nearly as possible that for every six
drops there is one impact on each of the major surfaces and that the surface to be
struck is approximately parallel to the impact surface.

4.2.2 Telephone Line Surge – Type A

4.2.2.1 Metallic:

4.2.2.1.1 Two metallic voltage surges (one of each polarity) shall be applied between any

pair of connections on which lightning surges may occur; this includes:

a) tip to ring;
b) tip-1 to ring-1; and

c) For a 4-wire connection that uses simplexed pairs for signaling, tip to ring-

1 and ring to tip-1.

` TIA-968-A

4.2.2.1.2 The surge shall have an open circuit voltage waveform in accordance with Figure

4.2 having a front time (t

) of 10 µs maximum and a decay time (t

) of 560 µs

minimum, and shall have a short circuit current waveshape in accordance with
Figure 4.3 having a front time (t

) of 10 µs maximum and a decay time (t

) of 560

µs minimum. The peak voltage shall be at least 800 V and the peak short circuit
current shall be at least 100 A.

4.2.2.1.3 Surges shall be applied as follows:

a) With the equipment in all states that can affect compliance with the

requirements of this standard. If an equipment state cannot be achieved by
normal means of power, it shall be achieved artificially;

b) With equipment leads not being surged (including telephone connections,

auxiliary leads, and terminals for connection to non-approved equipment)
terminated in a manner that occurs in normal use;

c) Under reasonably foreseeable disconnection of primary power sources,

with primary power cords plugged and unplugged, if so configured.

4.2.2.2 Longitudinal:

4.2.2.2.1 Two longitudinal voltage surges (one of each polarity) shall be applied to any pair

of connections on which lightning surges may occur. This includes the tip-ring pair
and the tip-1—ring-1 pair, to earth grounding connections, and to all leads
intended for connection to non-approved equipment, connected together. Surges
shall be applied as follows:

a) With the equipment in all states that can affect compliance with the

requirements of this Standard. If an equipment state cannot be achieved
by normal means of power, it shall be achieved artificially;

b) With equipment leads not being surged (including telephone connections,

auxiliary leads, and terminals for connection to non-approved equipment)
terminated in a manner that occurs in normal use;

c) Under reasonably foreseeable disconnection of primary power sources, as

for example, with primary power cords plugged and unplugged.

4.2.2.2.2 The surge shall have an open circuit voltage waveform in accordance with Figure

4.2 with a front time (t

) of 10 µs maximum and a decay time (t

) of 160 µs

minimum, and shall have a short circuit current waveshape in accordance with
Figure 4.3 having a front time (t

) of 10 µs maximum and a decay time (t

) of 160

µs minimum. The peak voltage shall be at least 1500 V and the peak short circuit
current shall be at least 200 A.

TIA-968-A

4.2.2.3 Failure Modes resulting from application of Type A telephone line surges:

Regardless of operating state, equipment and circuitry are allowed to be in violation
of the transverse balance requirements of sections 4.6.2 and 4.6.3 and, for terminal
equipment connected to Local Area Data Channels, the longitudinal signal power
requirements of section 4.5.5.2 if:

a) Such failure results from an intentional, designed failure mode that has the

effect of connecting telephone or auxiliary connections with earth ground;
and,

b) If such a failure mode state is reached, the equipment is designed so that

it would become substantially and noticeably unusable by the user, or an
indication is given (e.g. an alarm), in order that such equipment can be
immediately disconnected or repaired.

The objective of (a) is to allow for safety circuitry to either open-circuit, which would cause

a permanent on-hook condition, or to short-circuit to ground, as a result of an
energetic lightning surge. Off-hook tests would be unwarranted if the off-hook
state cannot be achieved. A short to ground has the potential for causing
interference resulting from longitudinal imbalance, and therefore designs shall
be adopted which will cause the equipment either to be disconnected or
repaired rapidly after such a state is reached, should it occur in service.

4.2.3 Telephone Line Surge – Type B

4.2.3.1 Metallic

Two metallic voltage surges (one of each polarity) shall be applied to equipment
between any pair of connections on which lightning surges may occur; this
includes:

a) tip to ring;

b) tip-1 to ring-1; and

c) For a 4-wire connection that uses simplexed pairs for signaling, tip to ring-1

and ring to tip-1.

The surge shall have an open circuit voltage waveform in accordance with Figure 4.2

having a front time (t

) of 9 µs

30% and a decay time (t

) of 720 µs ± 20% and

shall have a short circuit current waveshape in accordance with Figure 4.3
having a front time (t

) of 5 µs

30% and a decay time (t

) of 320 µs ± 20%.

The peak voltage shall be at least 1000 V and the peak short circuit current
shall be at least 25 A. The wave shapes are based on the use of ideal
components in Figure 4.1 with S2 in Position M. Surges shall be applied:

a) With the equipment in all states that can affect compliance with the

requirements of this standard. If an equipment state cannot be achieved by
normal means of power, it shall be achieved artificially.

b) With equipment leads not being surged (including telephone connections,

auxiliary leads, and terminals for connection to non-approved equipment)
terminated in a manner that occurs in normal use.

` TIA-968-A

c) Under reasonably foreseeable disconnection of primary power sources, as

for example, with primary power cords plugged and unplugged.

4.2.3.2 Longitudinal:

Two longitudinal voltage surges (one of each polarity) shall be applied to any pair of
connections on which lightning surges may occur. This includes the tip-ring pair
and the tip-1 ring-1 pair to earth grounding connections and to all leads intended for
connection to non-approved equipment, connected together. Surges shall be
applied as follows:

a) With the equipment in all states that can affect compliance with the

requirements of this Standard. If an equipment state cannot be achieved by
normal means of power, it shall be achieved artificially.

b) With equipment leads not being surged (including telephone connections,

auxiliary leads, and terminals for connection to non-approved equipment)
terminated in a manner that occurs in normal use.

c) Under reasonably foreseeable disconnection of primary power sources, as

for example with primary power cords plugged and unplugged.

For each output lead of the surge generator, with the other lead open, the
surge shall have an open circuit voltage waveform in accordance with Figure
4.2 having a front time (t

) of 9 µs ± 30% and a decay time (t

) of 720 µs ± 20%

and shall have a short circuit current waveshape in accordance with Figure 4.3
having a front time (t

) of 5 µs ± 30% and a decay time (t

) of 320 µs ± 20%.

The peak voltage shall be at least 1500 V and the peak short circuit current
shall be at least 37.5 A. The wave shapes are based on the use of ideal
components in Figure 4.1 with S2 in Position L.

4.2.3.3 Failure Modes resulting from application of Type B telephone line surges: Approved

terminal equipment and approved protective circuitry shall withstand the energy of
Surge Type B without causing permanent opening or shorting of the interface circuit
and without sustaining damage that will affect compliance with this standard.

` TIA-968-A

4.2.4 Power Line Surge

4.2.4.1 Six power line surges (three of each polarity) shall be applied between the phase

and neutral terminals of the ac power line while the equipment is being powered.
The surge shall have an open circuit voltage waveform in accordance with Figure
4.2 having a front time (t

) of 2 µs maximum and a decay time (t

) of 10 µs minimum

and shall have a short circuit current waveshape in accordance with Figure 4.3 with
a front time (t

) of 2 µs maximum and a decay time (t

) of 10 µs minimum. The peak

voltage shall be at least 2500 V and the peak short circuit current shall be at least
1000 A. Surges shall be applied:

4.2.4.1.1 With the equipment in all states that can affect compliance with the requirements

of this Standard. If an equipment state cannot be achieved by normal means of
power, it may be achieved artificially;

4.2.4.1.2 With equipment leads not being surged (including telephone connections,

auxiliary leads, and terminals for connection to non-approved/non-certified
equipment) terminated in a manner that occurs in normal use.

4.2.4.2 Failure Modes resulting from application of power line surge. Approved terminal

equipment and approved protective circuitry shall comply with all the criteria in this
standard, both prior to and after the application of the power line surge specified in
4.2.4, notwithstanding that this surge may result in partial or total destruction of the
equipment under test.

4.3 LEAKAGE CURRENT LIMITATIONS

Approved terminal equipment and approved protective circuitry shall have a voltage applied
to the combination of points listed in the table below. The test voltage shall be ac of 50 or
60 Hz rms.

a)  All telephone connections;
b)  All power connections;
c)  All possible combinations of exposed conductive surfaces on the exterior

of such equipment or circuitry including grounding connection points, but
excluding terminals for connection to other terminal equipment;

d) All terminals for connection to approved protective circuitry or non-

approved equipment;

e) All auxiliary lead terminals;
f)

All E&M lead terminals, and

g) All PR, PC, CY1 and CY2 leads.

TIA-968-A

Table 4.1 Voltage Applied For Various Combinations Of Electrical Connections

Voltage Source Connected Between:

AC Value*

(a) and (b) (See Notes 1, 2, 3)

1500

(a) and (c) (See Notes 1, 2)

1000

(a) and (d) (See Notes 1, 2)

1000

(a) and (e) (See Notes 1, 2)

1000

(a) and (f) (See Notes 1, 2)

1000

(a) and (g) (See Notes 1, 2)

1000

(b) and (c) (See Note 3)

1500

(b) and (d) (See Note 3)

1500

(b) and (e) (See Note 3)

1500

(b) and (f) (See Note 3)

1500

(b) and (g) (See Note 3)

1500

1000

(d) and (e) (See Note 2)

1000

(d) and (f) (See Note 2)

1000

(e) and (f) (See Note 2)

1000

* Value to which test voltage is gradually increased.

NOTES:

1. Gradually increase the voltage from zero to the values listed in the Table

over a 30-second time period, and then maintain the voltage for one minute.
The current in the mesh formed by the voltage source and these points shall
not exceed 10 mA

at any time during this 90-second interval.

2. Equipment states necessary for compliance with the requirements of this
section that cannot be achieved by normal means of power shall be achieved
artificially by appropriate means.

3. A telephone connection, auxiliary lead, or E&M lead that has an intentional
dc conducting path to earth ground at operational voltages (such as a ground
start lead), may be excluded from the leakage current test in that operational
state. Leads or connections excluded for this reason shall comply with the
requirements of 4.4.5.1.

4. A telephone connection, auxiliary lead, or E&M lead that has an intentional
dc conducting path to earth ground for protection purposes at the leakage

` TIA-968-A

current test voltages (such as through a surge suppressor), may have the
component providing the conducting path removed from the equipment for the
leakage current test in that operational state. Components removed for this
reason shall comply with the requirements of section 4.4.5.2.

5. Filter paths, such as capacitors used in EMI filters, are left in place during
leakage current testing, since these components can be a path for excessive
leakage.

6. For multi-unit equipment inter-connected by cables, that is evaluated and
approved as an interconnected combination or assembly, the specified 10 mA
peak maximum leakage current limitation other than between power connection
points and other points, may be increased as described here to accommodate
cable capacitance. The leakage current limitation may be increased to (10N +
0.13L) mA

where L is the length of interconnecting cable in the leakage path in

meters and N is the number of equipment units that the combination or
assembly will place in parallel across a telephone connection.

7. RF filters and surge protectors on the line side of power supplies may be
disconnected before making leakage measurements (section 4.3). As an
alternative to disconnecting these filters and surge protectors, this
measurement may be made using a dc voltage equal to the peak ac test
voltage.

4.4 HAZARDOUS VOLTAGE LIMITATIONS

4.4.1 General: Under no condition of failure of approved terminal equipment or approved

protective circuitry that can be conceived to occur in the handling, operation or repair
of such equipment or circuitry, shall the open circuit voltage on telephone
connections exceed 70 V

after one second, except for voltages for network control

signaling, alerting and supervision.

4.4.1.1 Type I E&M Leads.

Approved terminal equipment shall comply with the following

requirements for terminal equipment on the ‘‘A’’ or ‘‘B’’ side of the interface as
shown in Figure 1.5 and Figure 1.6.

4.4.1.1.1 The dc current on the E lead shall not exceed 100 mA.

4.4.1.1.2 The maximum dc potentials to ground shall not exceed the following when

measured across a resistor of 20 k

Ω

± 10%:

TIA-968-A

Table 4.2 Type I E&M, DC Potentials

E LEAD

M LEAD

TE on “B” side originates

signals to network on E

lead.

5 V

TE on “A” side originates

signals to network on M

lead

-56.5 V; no positive

potential with respect to

ground.

-56.5 V; no positive

potential with respect to

ground.

4.4.1.2 The maximum ac potential between E&M leads and ground reference shall not

exceed 5 V

4.4.1.2.1 M lead protection shall be provided so that voltages to ground do not exceed 60

V. For relay contact implementation, a power dissipation capability of 0.5 W shall
be provided in the shunt path.

4.4.1.2.2 If the approved terminal equipment contains an inductive component in the E

lead, it shall assure that the transient voltage across the contact as a result of a
relay contact opening does not exceed the following voltage and duration
limitations:

a) 300 V

b) A rate of change of one V per µs, and
c) 60 V level after 20 ms.

4.4.1.3 Type II E&M Leads. Approved terminal equipment shall comply with the following

requirements:

4.4.1.3.1 For terminal equipment on the ‘‘A’’ side of the interface, the dc current in the E

lead shall not exceed 100 mA. The maximum ac potential between the E lead and
ground shall not exceed 5 V

4.4.1.3.2 For terminal equipment on the ‘‘B’’ side of the interface, the dc current in the SB

lead shall not exceed 100 mA. The maximum ac potential between the SB lead
and ground shall not exceed 5 V

4.4.1.3.3 The maximum dc potentials to ground shall not exceed the following when

measured across a resistor of 20 k

Ω

± 10%:

` TIA-968-A

Table 4.3 Type II E&M, DC Potentials

E lead

M lead

SB lead

SG lead

TE on “B” side

of the interface

originates

signals to

network on E

lead.

5 V

-56.5 V; no

positive

potential with

respect to

ground

5 V

TE on “A” side

of the interface

originates

signals to

network on M

lead

-56.5 V, no

positive

potential with

respect to

ground

5 V

4.4.1.3.4 The maximum ac potential to ground shall not exceed 5 V

on the following leads,

from sources in the terminal equipment:

a) M, SG and SB leads for terminal equipment on the ‘‘A’’ side of the interface.
b) E, SG and M leads for terminal equipment on the ‘‘B’’ side of the inter-face.

4.4.1.3.5 If the approved terminal equipment contains an inductive component in the (E) or

(M) lead, it shall assure that the transient voltage across the contact as a result of
a relay contact opening does not exceed the following voltage and duration
limitations:

a) 300 V

b) A rate of change of one V / µs, and
c) A 60 V level after 20 ms.

4.4.1.4 Off premises station voltages

4.4.1.4.1 Talking battery or voltages applied by the PBX (or similar systems) to all classes

of OPS interface leads for supervisory purposes shall be negative with respect to
ground, shall not be more than -56.5 V dc with respect to ground, and shall not
have a significant ac component. The ac component shall not exceed 5 V

unless otherwise controlled by section 4.5.

4.4.1.4.2 Ringing signals applied by the PBX (or similar systems) to all classes of OPS

interface leads shall comply with requirements in section 4.4.4. Ringing voltages
shall be applied between the ring conductor and ground.

4.4.1.5 Direct Inward Dialing (DID). Voltages applied by the PBX (or similar systems) to

DID interface leads for supervisory purposes shall be negative with respect to
ground, shall not be more than -56.5 V dc with respect to ground, and shall not
have a significant ac component. The ac component shall not exceed 5 V

, where

TIA-968-A

not otherwise controlled by section 4.5.

4.4.1.6 Local Area Data Channel Interfaces

For Local Area Data Channel interfaces,

during normal operating modes including terminal equipment initiated maintenance
signals, approved terminal equipment shall ensure, except during the application of
ringing (limitations specified in section 4.4.4), with respect to telephone connections
(tip, ring, tip-1, ring-1) that:

4.4.1.6.1 Under normal operating conditions, the rms current per conductor between short-

circuit conductors, including dc and ac components, does not exceed 350 mA. For
other than normal operating conditions, the rms current between any conductor
and ground or between short-circuited conductors, including dc and ac
components, may exceed 350 mA for no more than 1.5 minutes;

4.4.1.6.2 The dc voltage between any conductor and ground does not exceed 60 V. Under

normal operating conditions it shall not be positive with respect to ground (though
positive voltages up to 60 V may be allowed during brief maintenance states);

4.4.1.6.3 AC voltages are less than 42.4 V

between any conductor and ground. Terminal

equipment shall comply while other interface leads are:

a) Un-terminated, and
b) Individually terminated to ground

Combined ac and dc voltages between any conductor and ground shall be:
less than 42.4 V

when the absolute value of the dc component is less than

21.2 V; and less than (32.8 + 0.454 x V dc) when the absolute value of the dc
component is between 21.2 and 60 V.

4.4.1.7 Ringdown Voiceband Private Line and Voiceband Metallic Channel Interface.

During normal operation, approved terminal equipment for connection to ringdown
voiceband private line interfaces or voiceband metallic channel interfaces shall
ensure that:

4.4.1.7.1 Ringing voltage shall not exceed the voltage and current limits specified in section

4.4.4, and is:

a) Applied to the ring conductor with the tip conductor grounded for 2-wire

interfaces, or

b) Simplexed on the tip and ring conductors with ground simplexed on the tip-1

and ring-1 conductors for 4-wire interfaces.

` TIA-968-A

4.4.1.7.2 Except during the signaling mode or for monitoring voltage, there shall be no

significant positive dc voltage (not over +5 V) with respect to ground:

a) For 2-wire ports between the tip lead and ground and the ring lead and

ground and

b) For 4-wire ports between the tip lead and ground, the ring lead and ground,

the tip-1 lead and ground, and the ring-1 lead and ground.

4.4.1.7.3 The dc current per lead, under short circuit conditions shall not exceed 140 mA.

4.4.2 Connection of non-approved equipment to approved terminal equipment or approved

protective circuitry. Leads to, or any elements having a conducting path to telephone
connections, auxiliary leads or E&M leads shall:

a) Be reasonably physically separated and restrained from and be neither

routed in the same cable as nor use the same connector as leads or
metallic paths connecting power connections;

b) Be reasonably physically separated and restrained from and be neither

routed in the same cable as nor use adjacent pins on the same connector
as metallic paths that lead to non-approved equipment, when interface
voltages are less than non-hazardous voltage source limits in section 4.4.3.

TIA-968-A

4.4.3 Non-Hazardous voltage Source: A voltage source shall be considered a non-

hazardous voltage source if it conforms with the requirements of sections 4.2, 4.3
and 4.4.2, with all connections to the source other than primary power connections
treated as ‘‘telephone connections,’’ and if such source supplies voltages no greater
than the following under all modes of operation and of failure:

a) AC voltages less than 42.4 V

;

b) DC voltages less than 60 V; and
c) Combined ac and dc voltages between any conductor and ground are less

than 42.4 V

when the absolute value of the dc component is less than 21.2

V, and less than (32.8 + 0.454 x V dc) when the absolute value of the dc
component is between 21.2 and 60 V.

4.4.4 Ringing Sources: Ringing sources shall meet all of the following restrictions:

4.4.4.1 Ringing Signal Frequency.

The ringing signal shall use only frequencies whose

fundamental component is equal to or below 70 Hz.

4.4.4.2 Ringing Signal voltage. The ringing voltage shall be less than 300 V

P-P

and less

than 200 V peak-to-ground across a resistive termination of at least 1 M

Ω

4.4.4.3 Ringing Signal Interruption Rate.

The ringing voltage shall be interrupted to create

quiet intervals of at least one second (continuous) duration each separated by no
more than 5 seconds. During the quiet intervals, the voltage to ground shall not
exceed the voltage limits given in section 4.4.1.4.1.

4.4.4.4 Ringing Signal Sources: Ringing voltage sources shall comply with the following

requirements:

a) If the ringing current through a 500

Ω

(and greater) resistor does not exceed

100 mA

P-P

, neither a ring trip device nor a monitoring voltage is required.

b) If the ringing current through a 1500

Ω

(and greater) resistor exceeds 100

P-P

, the ringing source shall include a current-sensitive ring trip device in

series with the ring lead that will trip ringing as specified in Figure 4.4 in
accordance with the following conditions:

If the ring trip device operates as

specified in Figure 4.4 with R = 500

Ω

(and greater), no monitoring voltage is required;

If, however, the ring trip device only operates as specified in Figure 4.4
with R = 1500

Ω

(and greater) then the ringing voltage source shall also

provide a monitoring voltage between 19 V dc and 56.5 V dc, negative
with respect to ground, on the tip or ring conductor.

` TIA-968-A

c) If the ringing current through a 500

Ω

(and greater) resistor exceeds 100

P-P

but does not exceed 100 mA

P-P

with 1500

Ω

(and greater)

termination, the ringing voltage source shall include either a ring trip device
that meets the operating characteristics specified in Figure 4.4 with 500

Ω

(and greater) resistor, or a monitoring voltage as specified in section
4.4.4.4 (b). If the operating characteristics specified in section 4.4 are not
met with both the 500

Ω

and 1500

Ω

terminations, then the terminal

equipment under test fails (See Table 4.4).

Figure 4.4 Ringing Voltage Trip Criteria

TIA-968-A

Table 4.4 Table Summary of Ring-Trip Requirements

Ringing Current

(mA P-P)

Function

Required

4.4.4.4

R = 500

Ω

and greater

R = 1500

Ω

and greater

Ring-

Trip

Monitor

voltage

Ring-Trip Device Operates

per Figure 4.4

4.4.4.4(a) <100 <100

Option

Optional

4.4.4.4(b)(1) N/A

>100 Yes

Option

Yes for both resistances

4.4.4.4(b)(2) N/A

>100 Yes

Yes

Yes for R = 1500

Ω

and

greater

No for R = 500

Ω

and greater

4.4.4.4(c) >100 <100

Either Ring-Trip

device or

Monitor voltage

shall be

provided

Yes for R = 500

Ω

and greater,

if Ring-Trip device is used

4.4.5 Intentional paths to ground (as required by section 4.2)

4.4.5.1 Connections with operational paths to ground: Approved terminal equipment and

approved protective circuitry having an intentional dc conducting path to earth
ground at operational voltages that was excluded during the leakage current test of
section 4.3 shall have a dc current source applied between the following points:

a) Telephone connections, including tip, ring, tip-1, ring-1, E&M leads and

auxiliary leads

b) Earth grounding connections

For each test point, the current shall be gradually increased from zero to 1 A,
then maintained for one minute. The voltage between (a) and (b) shall not
exceed 0.1 V at any time. In the event there is a component or circuit in the
path to ground, the requirement shall be met between the grounded side of the
component or circuit and the earth grounding connection.

` TIA-968-A

4.4.5.2 Connections with protection paths to ground. Approved terminal equipment and

protective circuitry having an intentional dc conducting path to earth ground for
protection purposes at the leakage current test voltage that was removed during
the leakage current test of section 4.3 shall, upon its replacement, have a 50 or 60
Hz voltage source applied between the following points:

a) Simplexed telephone connections, including tip and ring, tip-1 and ring-1,

E&M leads and auxiliary leads, and;

b) Earth grounding connections.

The voltage shall be gradually increased from zero to 120 V rms for approved
terminal equipment, or 300 V rms for protective circuitry, then maintained for
one minute. The current between (a) and (b) shall not exceed 10 mA

at any

time. As an alternative to carrying out this test on the complete equipment or
device, the test may be carried out separately on components, subassemblies,
and simulated circuits, outside the unit, provided that the test results would be
representative of the results of testing the complete unit.

4.5 SIGNAL POWER LIMITATIONS

4.5.1 General: Limits on signal power shall be met at the interface for all 2-wire network

ports and, where applicable to offered services, both transmit and receive pairs of all
4-wire network ports. Signal power measurements shall be made using terminations
as specified in each of the following limitations. The transmit and receive pairs for
4-wire network ports shall be measured with the pair not under test connected to a
termination equivalent to that specified for the pair under test. Through gain
limitations shall apply only in the direction of transmission toward the network.

4.5.2 Voiceband metallic signal power

4.5.2.1 Limitations at the interface on internal signal sources not intended for network

control signaling:

4.5.2.1.1 The power of all signal energy other than live voice, in the 200–3995 Hz

voiceband, delivered by approved terminal equipment or approved protective
circuitry to the appropriate loop simulator — other than non-permissive data
equipment or data protective circuitry shall not exceed -9 dBm when averaged
over any 3-second interval.

4.5.2.1.2 For 2-wire and 4-wire lossless tie trunk type interfaces, the maximum power of

other than live voice signals delivered to a 600

Ω

termination shall not exceed -15

dBm when averaged over any 3-second interval.

4.5.2.1.3 For OPS lines, the maximum power of other than live voice delivered to an OPS

line simulator circuit shall not exceed -9 dBm, when averaged over any 3-second
interval.

TIA-968-A

4.5.2.1.4 For approved test equipment or approved test circuitry the maximum signal power

delivered to a loop simulator circuit shall not exceed 0 dBm when averaged over
any 3-second interval.

4.5.2.1.5 For voiceband private lines using ringdown or inband signaling the maximum

power of other than live voice signals delivered to a 600

Ω

termination shall not

exceed -13 dBm when averaged over any 3-second interval.

4.5.2.1.6 For voiceband private lines using inband signaling in the band 2600 ±



150 Hz, the

maximum power delivered to a 600

Ω

termination shall not exceed -8 dBm during

the signaling mode. The maximum power delivered to a 600

Ω

termination in the

on-hook steady state supervisory condition shall not exceed -20 dBm. The
maximum power of other than live voice signals delivered to a 600

Ω

termination

during the non-signaling mode and for other inband systems shall not exceed –13
dBm when averaged over any 3-second interval.

4.5.2.2 Limitations on internal signal sources primarily intended for network control

signaling, contained in voice and data equipment.

4.5.2.2.1 For all operating conditions of approved terminal equipment and approved

protective circuitry, the maximum power in the frequency band below 3995 Hz
delivered to a loop simulator circuit shall not exceed the following when averaged
over any 3-second interval:

a) 0 dBm when used for network control (DTMF);
b) 0 dBm when DTMF is used for manual entry end-to-end signaling. When

the device is used for this purpose it shall not generate more than 40
DTMF digits per manual key stroke;

c) -9 dBm in all other cases.

4.5.2.2.2 For tie trunk applications, the maximum power delivered to a 600

Ω

termination

for approved terminal equipment and approved protective circuitry under all
operating conditions shall not exceed -4 dBm over any 3-second interval.

4.5.2.3 Approved one-port and multiport terminal equipment and protective circuitry with

provision for through transmission from other terminal equipment, excluding data
equipment and data protective circuitry that are approved in accordance with
section 4.5.

4.5.2.3.1 Where through-transmission equipment provides a dc electrical signal to

equipment connected therewith (e.g. for powering of electro-acoustic
transducers), dc conditions shall be provided which fall within the range of
conditions provided by a loop simulator circuit unless the combination of the
through-transmission equipment and equipment connected therewith is approved
as a combination which conforms to sections 4.5.2 and 4.5.2.2.

4.5.2.3.2 Through-transmission equipment to which remotely connected data terminal

equipment may be connected shall not be equipped with or connected to either a
Universal or Programmed Data Jack used in data configurations. (See section

TIA-968-A

Table 4.5 Programming Resistors

Programming Resistor

* (

Ω

)

Programmed Data

Equipment Signal

power output

Short 0

dBm

150 -1

dBm

336 -2

dBm

569 -3

dBm

866 -4

dBm

1240 -5

dBm

1780 -6

dBm

2520 -7

dBm

3610 -8

dBm

5490 -9

dBm

9200 -10

dBm

19800 -11

dBm

Open -12

dBm

*Tolerance 1%

4.5.2.5 Approved one-port and multi-port terminal equipment and protective circuitry with

provision for transmission from ports to other equipment that is separately
approved for the public switched network, or ports to other network interfaces.

4.5.2.5.1 Approved terminal equipment and approved protective circuitry shall have no

adjustments that will allow net amplification to occur in either direction of
transmission in the through-transmission path within the 200–3995 Hz voiceband
that will exceed the following:

` TIA-968-A

Table 4.6 Allowable Net Amplification Between Ports (See notes 1, 3, 4, and 5)

Tie Trunk Type Ports

Integrated

OPS

Ports

Public HCC

From (see note 5)

2/4-wire

Sub-rate

1.544
Mbps

Satellite

Sub-rate

1.544
Mbps

Tandem4

Services

Trunk

(2-wire)

(2)

Switched

Network

Ports

(2-wire)

Digital

PBX-CO

4-wire

2/4 wire tie

0 dB

3 dB

6 dB

Sub-rate 1.544 Mbps

Satellite 4W Tie

0 dB

3 dB

6 dB

Sub-rate 1.544 Mbps

Tandem 4W Tie

-3 dB

0 dB

3 dB

Integrated Services

Trunk

-3 dB

0 dB

3 dB

RTE Digital

0 dB

3 dB

0 dB

RTE (see note 2)

PSTN/

OPS

-3 dB

0 dB

-3 dB

OPS (see note 2)

-2 dB

1 dB

4 dB

1 dB

Public Switched

Network (2-wire)

3 dB

HCC Digital

PBX-CO (4-wire)

NOTES:

1) The source impedance for all measurements shall be 600

Ω

. All ports

shall be terminated in appropriate loop or private line channel simulator
circuits or 600

Ω

terminations.

2) These ports shall be for 2-wire on-premises station ports to separately

approved terminal equipment.

3) These through gain limitations shall be applicable to multiport systems

where channels are not derived by time or frequency compression
methods. Terminal equipment employing such compression techniques
shall assure that equivalent compensation for through gain parameters
shall be demonstrated.

4) Approved terminal equipment and approved protective circuitry may

have net amplification exceeding the limitations of section 4.5.2.5.1

TIA-968-A

provided that, for each network interface type to be connected, the
absolute signal power levels specified in section 4.5 are not exceeded.

5) The indicated gain shall be in the direction that results when moving

from the horizontal entry toward the vertical entry.

6) Approved terminal equipment or protective circuitry with the capability

for through transmission from voiceband private line channels or
voiceband metallic channels to other telephone network interfaces shall
ensure that the absolute signal power levels specified in section 4.5, for
each telephone network interface type to be connected, are not
exceeded.

Approved terminal equipment or protective circuitry with the capability
for through transmission from voiceband private line channels or
voiceband metallic private line channels to other telephone network
interfaces shall assure, for each telephone network interface type to be
connected, that signals with energy in the 2450 to 2750 Hz band are not
through transmitted unless there is at least an equal amount of energy
in the 800 to 2450 Hz band within 20 ms of application of signal.

4.5.2.5.2 The insertion loss in through connection paths for any frequency in the 800 to

2450 Hz band shall not exceed the loss at any frequency in the 2450 to 2750 Hz
band by more than 1 dB (maximum loss in the 800 to 2450 Hz band minus
minimum loss in the 2450 to 2750 Hz band plus 1 dB).

4.5.2.6 For Tie Trunk Interfaces – Limitation on idle circuit stability parameters: For idle

state operating conditions of approved terminal equipment and approved protective
circuitry, the following limitations shall be met:

4.5.2.6.1 For the two-wire interface:

` TIA-968-A

4.5.2.6.2 For the four-wire lossless interface:

4.5.2.6.3 The following definitions shall apply to return loss requirements:

a) RL the return loss of 2-wire terminal equipment at the interface with respect

to 600

Ω

+ 2.16 µF (i.e., Z

ref

= 600

Ω

+ 2.16 µF).

b) RL

the terminal equipment input (receive) port return loss with respect to

600

Ω

(i.e., Z

ref

= 600

Ω

c) RL

the terminal equipment output (transmit) port return loss with respect to

600

Ω

(i.e., Z

ref

= 600

Ω

d) tl the transducer loss between the receive and transmit ports of the 4-wire

PBX.

TIA-968-A

e) tl

is the transducer loss in the forward direction from the receive port to the

transmit port of the PBX.

f) Where

is the current sent into the receive port and I

is the current received

at the transmit port terminated at 600

Ω

g) tl

is the transducer loss in the reverse direction, from the transmit port to the

receive port of the PBX.

h) Where I

is the current sent into the transmit port and I

is the current

received at the receive port terminated at 600

Ω

. The source impedance of I

shall be 600

Ω

4.5.2.7 Approved terminal equipment and approved protective circuitry shall provide the

following range of dc conditions to off-premises station (OPS) lines.

4.5.2.7.1 DC voltages applied to the OPS interface for supervisory purposes and during

network control signaling shall meet the limits specified in section 4.4.1.4.1.

4.5.2.7.2 DC voltages applied to the OPS interface during the talking state shall meet the

following requirements:

4.5.2.7.2.1 The maximum open circuit voltage across the tip (T(OPS)) and ring (R(OPS))

leads for all classes shall not exceed 56.5 V, and

4.5.2.7.2.2 Except for class A OPS interfaces, the maximum dc current into a short circuit

across tip (T(OPS)) and ring (R(OPS)) leads shall not exceed 140 mA.

4.5.2.7.2.3 Except for Class A OPS interfaces, the dc current into the OPS line simulator

circuit shall be at least 20 mA for the following conditions (see Figure 1.7)

` TIA-968-A

+ R

Condition

Class B

Class C

1 600

1300

2 1800

2500

4.5.3 Signal power in the 3995–4005 Hz frequency band

4.5.3.1 Power resulting from internal signal sources contained in approved protective

circuitry and approved terminal equipment (voice and data), not intended for
network control signaling: For all operating conditions of approved terminal
equipment and approved protective circuitry that incorporate signal sources other
than sources intended for network control signaling, the maximum power delivered
by such sources in the 3995–4005 Hz band to an appropriate simulator circuit, shall
be 18 dB below maximum permitted power specified in section 4.5.2 for the
voiceband.

4.5.3.2 Terminal equipment with provision of through-transmission from other equipment:

The loss in any through-transmission path of approved terminal equipment and
approved protective circuitry at any frequency in the 600 to 4000 Hz band shall not
exceed, by more than 3 dB, the loss at any frequency in the 3995 to 4005 Hz band,
when measured into an appropriate simulator circuit from a source that appears as
600

Ω

across tip and ring.

4.5.4 Longitudinal voltage at frequencies below 4 kHz

4.5.4.1 The weighted rms voltage (see note) averaged over 100 ms that is resultant of all

of the component longitudinal voltages in the 100 Hz to 4 kHz band after weighting
according to the transfer function of f/4000 where f is the frequency in Hz, shall not
exceed the maximum indicated under the conditions stated in section 4.5.7.

NOTE:

Average magnitudes may be used for signals that have peak-to-rms ratios of
20 dB and less. The rms limitations shall be used instead of average values if
the peak-to-rms ratio of the interfering signal exceeds this value.

Frequency range

Maximum weighted

rms voltage

Impedance

100 Hz to 4 kHz

-30 dBV

500

Ω

4.5.5 Voltage in the 4 kHz to 30 MHz frequency range-general case –2-wire and 4-wire

lossless interface (except LADC).

TIA-968-A

Except as noted, rms voltage as averaged over 100 ms at the telephone connections
of approved terminal equipment and approved protective circuitry in all of the
possible 8-kHz bands within the indicated frequency range and under the conditions
specified in section 4.5.7 shall not exceed the maximum indicated below. For
sections 4.5.5.1.1 and 4.5.5.2.1, ‘‘f’’ shall be the center frequency in kHz of each of
the possible 8-kHz bands beginning at 8 kHz.

4.5.5.1 Metallic

voltage.

4.5.5.1.1 4 kHz to 270 kHz:

Center frequency (f)

of 8-kHz band

Max voltage in all

8-kHz bands

Metallic terminating

impedance

8 kHz to 12 kHz

-(6.4 + 12.6 log f) dBV

300

Ω

12 kHz to 90 kHz

(23 – 40 log f) dBV

135

Ω

90 kHz to 266 kHz

-55 dBV

135

Ω

4.5.5.1.2 270 kHz to 30 MHz. The rms value of the metallic voltage components in the

frequency range of 270 kHz to 30 MHz shall, averaged over 2 µs, not exceed -15
dBV. This limitation applies with a metallic termination having an impedance of
135

Ω

4.5.5.2 Longitudinal

voltage

4.5.5.2.1 4 kHz to 270 kHz.

Center frequency (f)

of 8-kHz band

Max voltage in all

8-kHz bands

Longitudinal terminating

impedance

8 kHz to 12 kHz

-(18.4 + 20 log f) dBV

500

Ω

12 kHz to 42 kHz

(3 – 40 log f) dBV

Ω

42 kHz to 266 kHz

-62 dBV

Ω

A filter between the TE and the network interface may be necessary to meet this

requirement.

` TIA-968-A

4.5.5.2.2 270 kHz to 6 MHz. The rms value of the longitudinal voltage components, in the

frequency range of 270 kHz to 6 MHz shall not exceed -30 dBV with a longitudinal
termination having an impedance of 90

Ω

4.5.6 LADC interface

The metallic voltage shall comply with the general requirements in section 4.5.6.1 as
well as the additional requirements specified in sections 4.5.6.2 and 4.5.6.3. The
requirements apply under the conditions specified in section 4.5.7. Terminal
equipment for which the magnitude of the source and/or terminating impedance
exceeds 300

Ω

, at any frequency in the range of 100 kHz to 6 MHz, at which the

signal (transmitted and/or received) has significant power, shall be deemed not to
comply with these requirements. A signal shall be considered to have ‘‘significant
power’’ at a given frequency if that frequency is contained in a designated set of
frequency bands that collectively have the property that the rms voltage of the signal
components in those bands is at least 90% of the rms voltage of the total signal. The
designated set of frequency bands shall be used in testing all frequencies.

4.5.6.1 Metallic voltages—frequencies below 4 kHz

4.5.6.1.1 Weighted rms voltage in the 10 Hz to 4 kHz frequency band. The weighted rms

metallic voltage in the frequency band from 10 Hz to 4 kHz, averaged over 100
ms that is the resultant of all the component metallic voltages in the band after
weighting according to the transfer function of f/4000 where f is the frequency in
Hz, shall not exceed the maximum indicated below under the conditions stated in
section 4.5.7.

Frequency Range

Maximum voltage

10 Hz to 4 kHz

+3 dBV

4.5.6.1.2 RMS voltage in 100 Hz bands in the frequency range 0.7 kHz to 4 kHz. The rms

metallic voltage averaged over 100 ms in the 100-Hz bands having center
frequencies between 750 Hz and 3950 Hz shall not exceed the maximum
indicated below.

Center freq (f) of 100-Hz bands

Max voltage in all 100-Hz bands

750 to 3950 Hz

-6 dBV

4.5.6.2

Metallic voltages—frequencies above 4 kHz—LADC interface

TIA-968-A

4.5.6.2.1 100-Hz bands over frequency range of 4 kHz to 270 kHz. The rms voltage as

averaged over 100 ms in all possible 100-Hz bands between 4 kHz and 270 kHz
for the indicated range of center frequencies and under the conditions specified in
section 4.5.7 shall not exceed the maximum indicated below:

Center freq (f) of all 100-Hz bands

Max voltage in all 100-Hz bands

4.05 kHz to 4.6 kHz

0.5 dBV

4.60 kHz to 5.45 kHz

(59.2-90 log f) dBV

5.45 kHz to 59.12 kHz

(7.6-20 log f) dBV

59.12 kHz to 266.00 kHz

(43.1-40 log f) dBV

Where f = center frequency in kHz of each of the possible 100-Hz bands.

4.5.6.2.2 8-kHz bands over frequency range of 4 kHz to 270 kHz. The rms voltage as

averaged over 100 ms in all of the possible 8-kHz bands between 4 kHz and 270
kHz for the indicated range of center frequencies and under the conditions
specified in section 4.5.7 shall not exceed the maximum indicated below:

Center freq (f) of 8-kHz bands

Max voltage in all 8-kHz bands

8 kHz to 120 kHz

(17.6—20 log f) dBV

120 kHz to 266 kHz

(59.2—40 log f) dBV

Where f = center frequency in kHz of each of the possible 8-kHz bands

4.5.6.2.3 RMS voltage at frequencies above 270 kHz. The rms value of the metallic voltage

components in the frequency range of 270 kHz to 30 MHz, averaged over 2 µs,
shall not exceed -15 dBV with a metallic termination having an impedance of
135

Ω

4.5.6.2.4 Peak voltage. The total peak voltage for all frequency components in the 4-kHz to

6-MHz band shall not exceed 4.0 V.

4.5.6.3 Longitudinal voltage.

` TIA-968-A

4.5.6.3.1 Frequencies below 4 kHz. The weighted rms voltage in the frequency band from

10 Hz to 4 kHz, averaged over 100 ms is the resultant of all the component
longitudinal voltages in the band after weighting according to the transfer function
of f/4000, where f is the frequency in Hz. The resultant weighted rms voltage shall
not exceed the maximum indicated below under the conditions stated in section
4.5.7.

Frequency Range

Maximum RMS voltage

10 Hz to 4 kHz

-37 dBV

4.5.6.3.2 4 kHz to 270 kHz.

Center freq (f)

of 8-kHz bands

Max voltage

in all 8-kHz bands

Longitudinal

terminating

impedance

8 to 12 kHz

-(18.4+20 log f) dBV

500

Ω

12 to 42 kHz

(3–40 log f) dBV

Ω

42 to 266 kHz

-62 dBV

Ω

Where f = center frequency in kHz of each of the possible 8-kHz bands.

4.5.6.3.3 270 kHz to 6 MHz. The rms value of the longitudinal voltage components in the

frequency range of 270 kHz to 6 MHz, averaged over 2 ms, shall not exceed -30
dBV with a longitudinal termination having an impedance of 90

Ω

4.5.7 Requirements in sections 4.5.4, 4.5.5 and 4.5.6 shall apply under the following

conditions:

4.5.7.1 All approved terminal equipment, except equipment to be used on LADC, and all

approved protective circuitry, shall comply with the limitations when connected to a
termination equivalent to the circuit depicted in Figure 4.5 and when placed in all
operating states of the equipment except during network control signaling. LADC
approved terminal equipment shall comply with the metallic voltage limitations
when connected to circuits of Figure 1.10 and shall comply with the longitudinal
limitations when connected to circuits of Figure 4.5, as indicated.

` TIA-968-A

4.5.7.2 All approved terminal equipment and approved protective circuitry shall comply with

the limitations in the off-hook state over the range of loop currents that would flow
with the equipment connected to an appropriate simulator circuit.

4.5.7.3 Approved terminal equipment and approved protective circuitry with provision for

through-transmission from other equipments shall comply with the limitations with a
1000 Hz tone applied from a 600

Ω

source (or, if appropriate a source which

reflects a 600

Ω

impedance across tip and ring) at the maximum level that would be

applied during normal operation. Approved protective circuitry for data shall also
comply with the tone level 10 dB higher than the overload point.

4.5.7.4 For approved terminal equipment or approved protective circuitry with non-

approved signal source input, such as music on hold, the out of band signal power
requirements shall be met using an input signal with a frequency range of 200 Hz to
20 kHz and the level set at the overload point.

4.5.7.5 Except during the transmission of ringing (section 4.4.4) and Dual Tone Multi-

frequency (DTMF) signals, LADC approved terminal equipment shall comply with
all requirements in all operating states and with loop current that may be drawn for
such purposes as loop back signaling. The requirements in section 4.5.6.1 except
in 4.5.6.1.1 and 4.5.6.1.2 shall also apply during the application of ringing. The
requirement in 4.5.4 and the requirements in 4.5.6.1.1 and 4.5.6.1.2 shall apply
during ringing for frequencies above 300 Hz and with the maximum voltage limits
raised by 10 dB. DTMF signals which are used for the transmission of alpha-
numeric information and which comply with the requirements in 4.5.6.1.1, and in
4.5.6.2 or 4.5.6.3 as applicable, shall be deemed to comply with the requirements
in 4.5.6.1.2 provided that, for automatically originated DTMF signals, the duty cycle
is less than 50%.

4.5.7.6 LADC approved terminal equipment shall comply with all applicable requirements,

except those specified in sections 4.5.6.1.1 and 4.5.6.1.2, during the transmission
of each possible data signal sequence of any length. For compliance with 4.5.6.3.1,
the limitation applies to the rms voltage averaged as follows:

a) For digital signals, baseband or modulated on a carrier, for which there are

defined signal element intervals, the rms voltage shall be averaged over each
such interval. Where multiple carriers are involved, the voltage is defined as
the power sum of the rms voltages for the signal element intervals for each
carrier.

b) For baseband analog signals, the rms voltage shall be averaged over each

period (cycle) of the highest frequency of the signal (-3 dB point on the
spectrum). For analog signals that are modulated on a carrier (whether or not
the carrier is suppressed), it shall be averaged over each period (cycle) of the
carrier. Where multiple carriers are involved, the voltage is defined as the
power sum of the rms voltage for each carrier.

c) For signals other than the types defined in section 4.5.7.6(a) and 4.5.7.6(b)

and (1) above, the peak amplitude of the signal shall not exceed +1 dBV.

4.5.7.7 Equipment shall comply with the requirements in section 4.5.6.1.1 and 4.5.6.1.2,

TIA-968-A

during any data sequence that may be transmitted during normal use with a
probability greater than 0.001. If the sequences transmitted by the equipment are
application dependent, the user instruction material shall include a statement of any
limitations assumed in demonstrating compliance of the equipment.

4.5.7.8 In addition to the conditions specified in section 4.5.7.5, LADC approved terminal

equipment which operates in one or more modes as a receiver, shall comply with
requirements in 4.5.6.3 with a tone at all frequencies in the range of potential
received signals and at the maximum power which may be received.

4.5.8 Interference limitations for terminal equipment connecting to digital services

4.5.8.1 Limitations on Terminal Equipment Connecting to Subrate Digital Services
In addition to the requirements in 4.5.8.1.1 and 4.5.8.1.2, subrate TE shall meet either the
PSD and average power requirements in 4.5.8.1.3 through 4.5.8.1.5 or the output pulse
template and average power requirements in 4.5.8.1.6 and 4.5.8.1.7.

4.5.8.1.1 Pulse repetition rate. The pulse repetition rate shall be synchronous with 2.4, 3.2,

4.8, 6.4, 9.6, 12.8, 19.2, 25.6, 38.4, 56.0, or 72 kbps per second.

4.5.8.1.2 Encoded analog content

If approved terminal equipment connecting to sub-rate services contains an analog-to-digital
converter, or generates signals directly in digital form that are intended for eventual
conversion into voiceband analog signals, the encoded analog content of the digital signal
shall be limited as specified in Section 4.5.10.

4.5.8.1.3 Equivalent PSD for maximum output.
When applied to a 135 ohm resistor, the instantaneous amplitude of the PSD, obtainable
from the registered terminal equipment, shall not exceed the PSD defined by the following
limiting function, in dBm/Hz:

10 log

( )

56000
fbaud

f3dB





















fbaud k

⋅





















⋅













⋅

Additional_Attenuation

−

where “A” is equal to ½ for 9.6 kbps and 12.8 kbps or 1 for all other rates, “fbaud” is equal to
the baud rate, “f3dB” is equal to 1.3 times the baud rate times 1.05, “f” is the frequency, and
“k” is defined in Table 4.7. Additional attenuation is required at certain baud rates in the
bands specified in Tables 4.8 and 4.9. PSD shall be measured for frequencies between ½
the baud rate and 20 times the baud rate. If 20 times the baud rate is less than 80 kHz, then
the upper frequency measurement bound shall be 80 kHz. The resolution bandwidth for the
PSD shall be less than or equal to 0.1 times the baud rate but no greater than 3 kHz.

4.5.8.1.4 Average Power for non-Secondary Channel Rates.

The average output power when a random signal sequence, (0) or (1) equiprobable

` TIA-968-A

in each pulse interval, is being produced as measured across a 135 ohm resistance
shall not exceed the values shown in Table 4.7.

4.5.8.1.5 Average Power for Secondary Channel Rates.

The customer data shall be a random signal sequence, (0) or (1) equiprobable in
each pulse interval. The network control bit shall equal 1, and the framing pattern
shall be (0) or (1) with equal probability. The average output power as measured
across a 135 ohm resistance shall not exceed the values shown in Table 4.7.

4.5.8.1.6 Template for maximum output pulse.

When applied to a 135

Ω

resistor, the instantaneous amplitude of the largest

isolated output pulse obtainable from the approved terminal equipment shall not
exceed by more than 10% the instantaneous voltage defined by a template
obtained as follows: The limiting pulse template shall be determined by passing
an ideal 50% duty cycle rectangular pulse with the amplitude/pulse rate
characteristics defined in Table 4.7 through a single real pole low pass filter
having a cutoff frequency in Hz equal to 1.3 times the bit rate. For bit rates of 2.4,
3.2, 4.8, 6.4, 9.6 and 12.8 kbps, the filtered pulses shall also be passed through a
filter providing the additional attenuation in Table 4.8.

TIA-968-A

Table 4.7—Values for k and average output power

Line rate (kbps)

User data rate (R)

(kbps)

Values for k

Maximum average

power (dBm)

2.4 2.4

0.00727798

6.9

3.2

2.4 with SC

0.00804454

7.4

4.8 4.8

0.00727798

6.9

6.4

4.8 with SC

0.00804454

7.4

9.6 9.6

0.00727798

0.9

12.8

9.6 with SC

0.00804454

1.4

19.2 19.2

0.00727798

6.9

25.6

19.2 with SC

0.00804454

7.4

38.4 38.4

0.00727798

6.9

51.2

38.4 with SC

0.00804454

7.4

56 56

0.00727798

6.9

56 with SC

0.00795272

7.4

72 64

0.00727798

6.9

SC: Secondary Channel

Table 4.8 Driving Pulse Amplitude for Subrate Terminal Equipment

Line Rate (kbps)

User Data Rate (kbps)

Amplitude (V)

2.4 2.4

1.66

3.2

2.4 with SC *

1.66

4.8 4.8

1.66

6.4

4.8 with SC *

1.66

9.6 9.6

0.83

12.8

9.6 with SC *

0.83

19.2 19.2

1.66

25.6

19.2 with SC *

1.66

38.4 38.4

1.66

51.2

38.4 with SC *

1.66

56 56

1.66

56 with SC *

1.66

72 64

1.66

* SC: Secondary Channel.

TIA-968-A

Table 4.10 Attenuation Curve for Subrate Terminal Equipment

24–32 kHz band

72–80kHz band

Attenuation factor (dB)

24 72

-18

25 73 -3

26 74 -1

27 75 0

28 76 0

29 77 0

30 78 -1

31 79 -3

32 80

-18

4.5.8.1.7 Average power

The average output power when a random signal sequence, (0)

or (1) equiprobable in each pulse interval, is being produced as measured across
a 135

Ω

resistance shall not exceed 0 dBm for 9.6 and 12.8 kbps or +6 dBm for

all other rates shown in Table 4.7.

4.5.8.1.8 Encoded analog content

If approved terminal equipment connecting to sub-rate

services contains an analog-to-digital converter, or generates signals directly in
digital form that are intended for eventual conversion into voiceband analog
signals, the encoded analog content of the digital signal shall be limited as
specified in Section 4.5.10.

4.5.8.2 Limitations on Terminal Equipment Connecting to 1.544 Mbps Digital Services and

ISDN PRA services.

4.5.8.2.1 Pulse repetition rate:

The free running line rate of the transmit signal shall be

1.544 Mbps with a tolerance of ± 32 ppm, i.e.,

± 50 bps.

4.5.8.2.2 Output pulse templates.

The approved terminal equipment shall be capable of

optionally delivering three sizes of output pulses. The output pulse option shall be
selectable at the time of installation.

4.5.8.2.2.1 Option A output pulse. When applied to a 100

Ω

resistor, the instantaneous

amplitude of the largest output pulse obtainable from the approved terminal
equipment shall fall within the pulse template illustrated in Figure 4.6. The mask
may be positioned horizontally as needed to encompass the pulse, and the
amplitude of the normalized mask may be uniformity scaled to encompass the
pulse. The baseline of the mask shall coincide with the pulse baseline.

4.5.8.2.2.2 Option B output pulse.

When applied to a 100

Ω

resistor, the instantaneous

` TIA-968-A

amplitude of the output from the approved terminal equipment obtained when
Option B is implemented shall fall within the pulse template obtained by passing
the bounding pulses permitted by Figure 4.6 through the following transfer
function.

out

where:

n

= 1.6049 x 10

= 7.9861 x 10

-1

= 9.2404 x 10

-8

= 2.1612 x 10

= 1.7223

= 4.575 x 10

-7

= 3.8307 x 10

-14

= j

f = frequency

(Hz)

4.5.8.2.2.3 Option C output pulse.

When applied to a 100

Ω

resistor, the instantaneous

amplitude of the output from the approved terminal equipment obtained when
Option C is implemented shall fall within the pulse template obtained by passing
the pulses obtained in Option B through the transfer function in Option B a
second time.

TIA-968-A

Maximum Curve

Nanoseconds (ns)

-500

-250

-175

-75

175

220

500

750

Normalized amplitude 0.05

0.05

0.8

1.2 1.2 1.05 1.05

-0.05

0.05 0.05

Minimum Curve

Nanoseconds

(ns) -500 -150 -150 -100

0 100 150 150 300 396 600 750

Normalized amplitude -.05 -.05

0.5

0.9 0.95

0.9 0.5 -0.45 -0.45

-0.26

-0.05 -0.05

The pulse amplitude shall be 2.4 to 3.6 V. (Use constant scaling factor to fit
normalized template.)

Figure 4.6 Isolated Pulse Template And Corner Points For ISDN PRA and1.544 Mbps

Equipment

` TIA-968-A

4.5.8.2.3 Adjustment of signal voltage

The signal voltage at the network interface shall be limited so that the range of
pulse amplitudes received at the first telephone company repeater is controlled
to ± 4 dB. This limitation shall be achieved by implementing the appropriate
output pulse option as a function of telephone company cable loss as specified
at time of installation.

Terminal Equipment

Cable loss at 772 kHz (dB)

Output pulse

Loss at 772 kHz

15 to 22

Option A

7.5 to 15

Option B

7.5

0 to 7.5

Option C

4.5.8.2.4 Output power.

The output power in a 3-kHz band about 772 kHz when an all ones signal
sequence is being produced as measured across a 100

Ω

terminating

resistance shall not exceed +19 dBm. The power in a 3 kHz band about 1.544
MHz shall be at least 25 dB below that in a 3-kHz band about 772 kHz.

4.5.8.2.5 Encoded analog content.

If approved terminal equipment connected to 1.544 Mbps digital services or
ISDN PRA services contains an analog-to-digital converter, or generates
signals directly in digital form that are intended for eventual conversion into
voiceband analog signals, the encoded analog content of the sub-rate channels
within the 1.544 Mbps or ISDN PRA signal shall be limited as specified in
Section 4.5.10..

4.5.8.2.6 Unequipped sub-rate channels. The permissible code words for unequipped

µ-255 encoded sub-rate channels of terminal equipment connected to 1.544 Mbps
digital services for ISDN PRA shall be limited to those corresponding to signals of
either polarity, of magnitude equal to or less than X48, where code word, XN is
derived by:

XN = (255 – N) base 2

XN = (127 – N) base 2

4.5.8.3 Limitations on TE Connecting to PSDS (Types I, II and III).

If PSDS (Types I, II and III) terminal equipment contains an analog to digital
converter, or generates signals directly in digital form that are intended for eventual
conversion into voiceband analog signals, the encoded analog content of the digital
signal shall be limited as specified in Section 4.5.10.

4.5.8.3.1 Pulse repetition rate.

TIA-968-A

For PSDS (Type II) the pulse repetition rate shall be a maximum of (144,000
±5) pulses per second; for PSDS (Type III) the pulse repetition rate shall be a
maximum of (160,000 ± 5) pulses per second.

4.5.8.3.2 Template for maximum output pulse.

When applied to a 135

Ω

resistor, the instantaneous amplitude of the largest

isolated output pulse obtainable from the approved terminal equipment shall
fall within the template of section 4.5.8.3.2 (a) for PSDS Type II or 4.5.8.3.2
(b) for PSDS Type III. The limiting pulse template shall be defined by passing
an ideal 50% duty cycle rectangular pulse within the amplitude/pulse rate
characteristics of (a) or (b) through a 1-pole low-pass filter with a -3 dB
frequency of 260 kHz.

Pulse Characteristics Template

4.5.8.3.2 (a)

PSDS Type II

4.5.8.3.2 (b)

PSDS Type III

Pulse Height

2.6 V ± 5%

2.4 V ± 5%

Pulse Width

(3472.2 ± 150) ns

(3125 ±100) ns

Max Rise or Fall Time -

(From 10% to 90% points)

100 ns

(1.2 ± 0.2) µs

4.5.8.4 Limitations on terminal equipment connected to ISDN BRA.

If approved terminal equipment connecting to an ISDN BRA interface contains an
analog-to-digital converter, or generates signals directly in digital form that are
intended for eventual conversion into voiceband analog signals, the encoded analog
content of the bearer channels within the ISDN BRA signal shall be limited as
specified in Section 4.5.10.

4.5.9 Signal Power Limitations for ADSL Terminal Equipment

ADSL modems shall operate within the aggregate signal power limitations of
4.5.9.1, the power spectral density limitations of 4.5.9.2 and the longitudinal output
voltage limitations of 4.5.9.3.

4.5.9.1 Aggregate signal power

ADSL modems shall operate with an aggregate signal power of less than +13.0
dBm into 100

Ω

over the frequency range of 25.875 to 138 kHz.

` TIA-968-A

4.5.9.2 Power spectral density

ADSL modem’s power spectral density (PSD) shall not exceed the PSD Mask as
defined by the table below:

Frequency Band

(kHz)

Equation for the PSD Mask

(dBm/Hz)

0.200 < f < 4

-97.5

4 < f < 25.875

-92.5 + 21.5 x log

(f/4)

25.875 < f < 138

-34.5

138 < f < 307

-34.5 - 48 x log

(f/138)

307 < f < 1221

-90

1221 < f < 1630

-90 peak, with max power in the [f,f+1 MHz] window of

(-90 - 48 X log

(f/1221) + 60) dBm

1630 < f < 30000

-90 peak, with max power in the [f,f+1 MHz] window of -50

dBm

NOTES:

1.) All PSD measurements are in 100

Ω

2.) The breakpoint frequencies and PSD values are exact; the indicated
slopes are approximate.
3.) Above 25.875 kHz, the peak PSD shall be measured with a minimum
resolution bandwidth of 10 kHz.
4.) The power in a 1 MHz sliding window is averaged over a 1 MHz
bandwidth, starting at the measurement frequency.

4.5.9.3 Longitudinal output voltage

ADSL modems shall meet the voiceband longitudinal voltage limitations of 4.5.4.1
as well as the limitations of 4.5.5.2.1 for a center frequency of 8 kHz, which covers
the frequency span from 4 to 12 kHz. In addition, using the illustrative longitudinal
output voltage measurement circuit in Figure 4.5, ADSL modems shall limit
longitudinal output voltage to the values shown in the table below:

Frequency Band
(kHz)

Maximum Longitudinal Output Voltage (rms) in all 4
kHz
bands averaged over a minimum period of 1 second

10 < f < 211

-50 dBV (or -51.3 dBV using a 3 kHz bandwidth)

211 < f < 844

-80 dBV (or -81.3 dBV using a 3 kHz bandwidth)

NOTES:

1.) The first frequency band is the operating band as defined by the
frequency points at which the PSD is approximately 30 dB down from the
peak mask value. Alternatively, the measured 30 dB points may be used to
define the operating band’s lower and upper frequency points.
2.) The upper frequency point is four times the upper, operating band
frequency.
3.) The alternative requirements of -51.3 dBV and -81.3 dBV include a -1.3
dB correction factor associated with using a 3 kHz bandwidth rather than the
ideal 4 kHz bandwidth.

TIA-968-A

4.5.10.

Encoded Analog Content Limits.

If approved terminal equipment contains an analog-to-digital converter or generates a data
bit stream that is intended for eventual conversion into voiceband analog signals in the
PSTN, the encoded analog content of the digital signal shall be limited as specified in this
clause.

The maximum equivalent power of encoded analog content derived by a zero level decoder
test configuration shall not exceed the following limits when averaged over any 3-second
time interval:

-12 dBm for all signals other than live voice, V.90 or V.92 modems, or network
control signals.

- 6 dBm for V.90 or V.92 modems.

-3 dBm for network control signals.

The zero level decoder test configuration is intended to simplify measurement of the
maximum encoded analog signal. The use of a zero level encoder for test purposes shall
not be interpreted as permission to exceed the encoded analog content limits given above
when analog or digital loss is inserted in the PSTN connection by wireline carriers.

` TIA-968-A

4.6 TRANSVERSE BALANCE LIMITATIONS

4.6.1 Technical description and application

The Transverse Balance

m-l

, coefficient is expressed as:

Balance

m l

= 20 log

[

/ e

]

4.6.1.1 Where

is the longitudinal voltage produced across a longitudinal termination Z

and e

is the metallic voltage across the tip-ring or tip-1 and ring-1 interface of the

input port when a voltage (at any frequency between f

and f

, see Table 4.11) is

applied at all values of dc loop current that the port under test is capable of drawing
when attached to the appropriate loop from a balanced source with a metallic
impedance Z

(see Table 4.11) The source voltage shall be set such that e

= E

(Volts) (see Table 4.11 when a termination of Z

is substituted for the terminal

equipment.)

4.6.1.2 The minimum transverse balance coefficient specified in this section (as

appropriate) shall be equaled or exceeded for all 2-wire network ports, OPS line
ports and the transmit pair (tip and ring) and receive pair (tip-1 and ring-1) of all 4-
wire network ports simulator circuits at all values of dc loop current that the port
under test is capable of drawing when attached to the appropriate loop (See Figure
1.4). An illustrative test circuit that satisfies the above conditions is shown in Figure
4.7 for analog and Figure 4.8 for digital and sub-rate; other means may be used to
determine the transverse balance coefficient specified herein, provided that
adequate documentation of the appropriateness, precision, and accuracy of the
alternative means is provided.

4.6.1.3 The minimum transverse balance requirements specified below shall be equaled or

exceeded under all reasonable conditions of the application of earth ground to the
equipment or protective circuitry under test.

TIA-968-A

Table 4.11 Transverse Balance Test Criteria

Analog voiceband

Sub-rate digital

1.544 Mbps digital

Longitudinal

Termination - Z

500

Ω

See Table 4.11

Ω

Metallic Source
Impedance - Z

600

Ω

135

Ω

100

Ω

Lower Frequency -

200 Hz

12 kHz

Upper Frequency -

4 kHz

(see note)

1.544 MHz

Metallic voltage for

Test - E

0.775 V

0.367 V

0.316 V

NOTE:

The upper frequency shall equal the digital line rate for the sub-rate service
under test (See Table 4.12.)

4.6.2 Analog voiceband equipment

All approved analog voiceband equipment shall be tested in the off-hook state. The
minimum transverse balance requirement in the off-hook state shall be 40 dB,
throughout the range of frequencies specified in Table 4.11. For some categories of
equipment, transverse balance requirements also apply to the on-hook state. When
both off-hook and on-hook requirements apply, they shall be:

State Frequency

(f)

Balance

Off-hook

200 Hz

≤

4000 Hz

40 dB

On-hook

200 Hz

≤

1000 Hz

60 dB

On-hook

1000 Hz

≤

4000 Hz

40 dB

4.6.2.1 For analog one-port 2-wire terminal equipment with loop-start, ringdown, or inband

signaling or for voiceband metallic channel applications, both off-hook and on-hook
requirements shall apply.

4.6.2.2 For analog one port equipment with ground-start and reverse-battery signaling only

off-hook requirements shall apply.

4.6.2.3 For analog approved protective circuitry for 2-wire applications with loop-start,

ringdown, or inband signaling; or for voiceband metallic channel applications, both
off-hook and on-hook requirements shall apply. Criteria shall be met with either
terminal of the interface to other equipment connected to earth ground. The
interface to other equipment shall be terminated in an impedance that will be

` TIA-968-A

reflected to the telephone connection as 600

Ω

in the off-hook state of the

approved protective circuit, and the interface shall not be terminated in the on-hook
state. The arrangement of Figure 4.12 shall be used.

4.6.2.4 For analog approved protective circuitry with ground-start and reverse-battery

signaling only off-hook requirements shall apply. Criteria shall be met with either
terminal of the interface to other equipment connected to earth ground. The
interface to other equipment shall be terminated in an impedance that will be
reflected to the telephone connection as 600

Ω

in the off-hook state of the

approved protective circuit. The arrangement of Figure 4.12 shall be used.

4.6.2.5 For analog multi-port equipment with loop-start signaling both off-hook and on-hook

requirements shall apply. Criteria shall be satisfied for all ports when all the ports
not under test are terminated in their appropriate networks, as will be identified
below, and when interface connections other than the ports are terminated in
circuits appropriate to that interface. The minimum transverse balance coefficients
shall also be satisfied for all values of dc loop current that the approved equipment
is capable of drawing through each of its ports when these ports are attached to the
loop simulator circuit specified in this standard. The termination for all ports other
than the particular one whose transverse balance coefficient is being measured
shall have a metallic impedance of 600

Ω

and a longitudinal impedance of 500

Ω

Figure 4.9 shows this termination.

4.6.2.6 For analog multi-port equipment with ground-start and reverse-battery signaling,

only off-hook requirements shall apply. Criteria shall be satisfied for all ports when
all ports not under test are terminated in their appropriate networks as will be
identified below, and when interface connections other than the ports are
terminated in circuits appropriate to that interface. The minimum transverse
balance coefficients shall be satisfied for all values of dc loop current that the
approved equipment is capable of drawing through each of its ports when these
ports are attached to the loop simulator circuit specified in this standard. The
terminations for all ports other than the particular one whose transverse balance
coefficient is being measured shall have a metallic impedance of 600

Ω

and a

longitudinal impedance of 500

Ω

. Figure 4.9 shows this termination.

4.6.2.7 For analog approved terminal equipment and protective circuitry for 4-wire network

ports, both the off-hook and on-hook requirements shall apply. The pairs not under
test shall be terminated in a metallic impedance of 600

Ω

. Other conditions are as

follows:

4.6.2.7.1 For analog approved protective circuitry with loop-start, ground-start, reverse

battery, ringdown, or inband signaling; or for voiceband metallic channel
applications. Criteria shall be met with either terminal of the interface to other
equipment connected to earth ground. The interface to other equipment shall be
terminated in an impedance that will result in 600

Ω

at each of the transmit and

receive pairs of the 4-wire telephone connection in the off-hook state of the
approved protective circuit, and the interface shall not be terminated in the on-
hook state. The arrangement of Figure 4.10 shall be used.

TIA-968-A

4.6.2.7.2 For analog multiport equipment with loop start, ground start, and reverse battery,

ringdown, or inband signaling; or for voiceband metallic channel applications.
Criteria shall be satisfied for all network ports when all the ports not under test are
terminated as defined below, and when interface connections other than the
network ports are terminated in circuits appropriate to the interface. The criteria
shall also be satisfied for all values of dc loop current that the approved
equipment is capable of drawing through each port when the port is connected to
the appropriate 4-wire loop simulator circuit. The terminations for both pairs of all
network ports not under test shall have a metallic impedance of 600

Ω

and a

longitudinal impedance of 500

Ω

. Figure 4.9 shows this termination.

4.6.2.8 For analog PBX equipment (or similar systems) with class B or class C off-

premises interfaces, only off-hook requirements shall apply. Criteria shall be
satisfied for all off-premises station interface ports when these ports are terminated
in their appropriate networks for their off-hook state, and when all other interface
connections are terminated in circuits appropriate to that interface. The minimum
transverse balance coefficients shall also be satisfied for all values of dc loop
current that the approved PBX is capable of providing through off-premises station
ports when these ports are attached to the off-premises line simulator circuit
specified in this standard.

4.6.2.9 For Type Z equipment with loop-start signaling, both off-hook and on-hook

requirements shall apply. Equipment that has on-hook impedance characteristics
that do not conform to the requirements of section 4.7 (e.g. Type Z), shall comply
with minimum transverse balance requirements of 40 dB in the voiceband. See
section 4.7.7 for conditions upon approval of ‘‘Type Z’’ equipment.

4.6.3 Digital

equipment

The minimum transverse balance requirements for approved terminal equipment
connected to digital terminal equipment shall be equaled or exceeded for the range
of frequencies applicable for the equipment under test and under all reasonable
conditions of the application of earth ground to the equipment. All such terminal
equipment shall have a transverse balance in the acceptable region of either Figure
4.11(a), or Figure 4.11(b), as appropriate, for the range of frequencies shown in
Table 4.12, for the specified digital terminal equipment in question. The metallic
impedance used for the transverse balance measurements for all sub-rate, PSDS
and BRA services shall be 135

Ω

and for 1.544 Mbps (including ISDN PRA) shall be

100

Ω

. The longitudinal termination for 1.544 Mbps (including ISDN PRA), ISDN

BRA, PSDS terminal equipment and sub-rate services shall be as defined in Table
4.12.

4.6.4 ADSL

equipment

addition to meeting the transverse balance limitations for analog voiceband

equipment in Section 4.6.2, ADSL terminal equipment’s transverse balance shall
equal or exceed the values in Figure 4.11(a) over the entire range of frequencies
between 13.6 kHz to 1625 kHz (see Table 4.12). Alternatively, a narrower frequency
range may be used that is defined by the points at which the measured power
spectral density is 20 dB down from the maximum level associated with both the
maximum rate upstream and downstream signals. The metallic impedance used for

TIA-968-A

Table 4.12 Frequency Ranges Of Transverse Balance Requirements

for equipment connecting to digital services

Digital Interface

Frequency range

(kHz)

Longitudinal

Termination (R

)

(

Ω

)

Metallic

Termination (R

)

(

Ω

)

2.4

0.2 to 2.4

500

135

2.4 + SC

0.2 to 3.2

500

135

4.8

0.2 to 4.8

500

135

4.8 + SC

0.2 to 6.4

500

135

9.6

0.2 to 9.6

500

135

9.6 + SC (note)

0.2 to 12.8

500/90

135

19.2 (see note)

0.2 to 19.2

500/90

135

19.2 + SC (see

note)

0.2 to 25.6

500/90

135

38.4 (see note)

0.2 to 38.4

500/90

135

38.4 + SC (see

note)

0.2 to 51.2

500/90

135

56 (see note)

0.2 to 56

500/90

135

56 + SC (see note)

0.2 to 72

500/90

135

64 (see note)

0.2 to 72

500/90

135

BRA

0.2 to 192

500/90

135

DS1 (1544 kHz)

12 to 1544

100

ADSL

13.6 to 1625

100

NOTE:

For 0.2 to 12 kHz the longitudinal termination (R

) shall be 500

Ω

and above 12

kHz the longitudinal termination (R

) shall be 90

Ω

` TIA-968-A

600

Ω

: 600

Ω

split audio transformer

, C

8 µF, 400 V dc, matched to within 0.1%

, C

100 to 500 pF adjustable trimmer capacitors

Osc

Audio oscillator with source resistance R

less than or equal to 600

Ω

Selected such that Z

OSC

+ R

= 600

Ω

500

Ω

NOTES:

1. V

shall not be measured at the same time as V

2. The test circuit shall be balanced to 20 dB greater than the

equipment standard for all frequencies specified (using trimmer
capacitors C

and C

), with a 600

Ω

resistor substituted for the

equipment under test.

3. Exposed conductive surfaces on the exterior of the equipment

under test shall be connected to the ground plane for this test.

4. When the Terminal Equipment makes provision for an external

connection to ground, the Terminal Equipment shall be connected
to ground. When the Terminal Equipment makes no provision for
an external ground, the Terminal Equipment shall be placed on a
ground plane that is connected to ground and has overall
dimensions at least 50% greater than the corresponding
dimensions of the Terminal Equipment. The Terminal Equipment
shall be centrally located on the ground plane without any
additional connection to ground.

Figure 4.7 Illustrative Test Circuit for Transverse Balance (Analog)

TIA-968-A

100/135

Ω

:100/135

Ω

wide-band transformer

(100

Ω

for 1.544 Mbps devices and 135

Ω

for sub-rate devices.)

20 pF
Differential

Optimally a dual-stator air-variable RF capacitor that maintains a constant
capacitance between stators while providing a variable capacitance from
either stator to ground.

3 pF

Composition RF capacitor

CAL

100/135

Ω

(See Note 2)

90/500

Ω

: A non-inductive precision resistor

(chosen according to Table 4.12).

NOTES:

1. The 3 pF capacitor may be placed on either line of the test set, as

required, to obtain proper balancing of the bridge.

2. Use an R

CAL

value of 100

Ω

for 1.544 Mbps devices and 135

Ω

for sub-

rate devices.

3. The effective output impedance of the tracking generator shall match

the appropriate test impedance. See Note 2. The spectrum analyzer's
input shall be differentially balanced to measure V

4. The impedance of the Tracking Generator shall be chosen to match the

Metallic Termination (R

) according to Table 4.12.

5. The transformer should be a wide band transformer with a 1:1

impedance ratio.

Figure 4.8 Illustrative Test Circuit for Transverse Balance (Digital)

` TIA-968-A

NOTES:

= R

for analog voiceband

300 k

Ω

, 300

Ω

350

Ω

for sub-rate digital

100 k

Ω

, 67.5

Ω

56.3

Ω

for 1.544 Mbps

100 k

Ω

, 50

Ω

is used to adjust termination balance. Balance of this termination shall be

adjusted to: at least 60 dB between 200 and 1000 Hz; at least 40 dB between
1000 and 4000 Hz; and at least 35 dB at 1.544 MHz.

Figure 4.9 Off-Hook termination of Multiport Equipment for Ports Not under Test

` TIA-968-A

4.7 ON-HOOK IMPEDANCE LIMITATIONS

4.7.1 General: Requirements in this section shall apply to the tip and ring conductors of

2-wire interfaces. These requirements also shall apply to 4-wire loop-start or ground-
start interfaces, in the following configuration:

4.7.1.1 The tip and ring conductors shall be connected together and treated as one of the

conductors of a tip and ring pair.

4.7.1.2 The tip-1 and ring-1 conductors shall be connected together and treated as the

other conductor of a tip and ring pair.

NOTE:

Throughout this section, references will be made to simulated ringing. Ringing
voltages which shall be used and impedance limitations associated with
simulated ringing are shown in Table 4.13.

Table 4.13 Simulated Ringing Voltages and Impedance Limitations

Ringing type

Range of compatible

ringing frequencies

(Hz)

Simulated ringing

voltage

superimposed on

56.5 V dc

Impedance limitation

(

Ω

)

20± 3

40 to 130 V rms

1400

30± 3

40 to 130 V rms

1000

15.3 to 34

40 to 130 V rms

1600

>34 to 49

62 to 130 V rms

1600

>49 to 68

62 to 150 V rms

1600

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4.7.2 Limitations on individual equipment intended for operation on loop-start telephone

facilities Approved terminal equipment and approved protective circuitry shall
conform to the following limitations.

4.7.2.1 On-hook resistance, metallic and longitudinal (up to 100 V dc). The on-hook dc

resistance between the tip and ring conductors of a loop start interface, and
between each of the tip and ring conductors and earth ground, shall be greater than
5 M

Ω

for all dc voltages up to and including 100 V.

4.7.2.2 On-hook resistance, metallic and longitudinal (100 V to 200 V dc).

The on-hook dc

resistance between tip and ring conductors of a loop start interface, and between
each of the tip and ring conductors and earth ground shall be greater than 30 k

Ω

for all dc voltages between 100 and 200 V.

4.7.2.3 DC current during ringing.

During the application of simulated ringing, as listed in

Table 4.13, to a loop start interface, the total dc current shall not exceed 3.0 mA.
The equipment shall comply for each ringing type that is listed as part of the ringer
equivalence.

4.7.2.4 Ringing frequency impedance (metallic).

During the application of simulated

ringing, as listed in Table 4.13 to a loop start interface, the impedance between the
tip and ring conductors (defined as the quotient of applied ac voltage divided by
resulting true rms current) shall be greater than or equal to the value specified in
Table 4.13. The equipment shall comply for each ringing type that is listed as part
of the ringer equivalence.

4.7.2.5 Ringing Frequency Impedance (longitudinal).

During the application of simulated

ringing, as listed in Table 4.13, to a loop start interface, the impedance between
each of the tip and ring conductors and ground shall be greater than 100 k

Ω

. The

equipment shall comply with each ringing type listed in the ringer equivalence.

` TIA-968-A

4.7.3 Limitations on individual equipment intended for operation on ground start telephone

facilities

Approved terminal equipment and approved protective circuitry shall conform to
the following limitations:

4.7.3.1 DC current during ringing

During the application of simulated ringing, as listed in Table 4.13, to a ground
start interface, the total dc current flowing between tip and ring conductors shall
not exceed 3.0 mA. The equipment shall comply for each ringing type listed as
part of the ringer equivalence.

4.7.3.2 Ringing frequency impedance (metallic)

During the application of simulated ringing, as listed in Table 4.13, to a ground
start interface, the total impedance of the parallel combination of the ac
impedance across tip and ring conductors and the ac impedance from the ring
conductor to ground (with ground on the tip conductor) shall be greater than the
value specified in Table 4.13. The equipment shall comply for each ringing
type listed as part of the ringer equivalence.

4.7.4 Ringer Equivalence Definition

The ringer equivalence number shall be the value determined in section 4.7.4.1
or 4.7.4.2, as appropriate, followed by the ringer type letter indicator
representing the frequency range for which the number is valid. If Ringer
Equivalence is to be stated for more than one Ringing Type, testing shall be
performed at each frequency range to which Ringer Equivalence is to be
determined in accordance with the above, and the largest resulting Ringer
Equivalence Number so determined shall be associated with each Ringing
Type letter designation for which it is valid.

4.7.4.1 For individual equipment intended for operation on loop-start telephone facilities,

the ringer equivalence shall be five times the impedance limitation listed in Table
4.13, divided by the minimum measured ac impedance, as defined in section
4.7.2.1.3, during the application of simulated ringing as listed in Table 4.13.

4.7.4.2 For individual equipment intended for operation on ground-start telephone facilities,

the ringer equivalence shall be five times the impedance limitation listed in Table
4.13, divided by the minimum measured ac impedance, defined in section 4.7.3.2,
during the application of simulated ringing as listed in Table 4.13.

4.7.5 Maximum ringer equivalence

All approved terminal equipment and approved protective circuitry that can
affect the ringing frequency impedance shall be assigned a Ringer
Equivalence. The sum of all such Ringer Equivalences on a given telephone
line or loop shall not exceed 5. In some cases, a system that has a total Ringer
Equivalence of 5 or more may not be usable on a given telephone line or loop.

4.7.6 OPS interfaces for PBX with DID (ring trip requirement)

PBX ringing supplies whose output appears on the off-premises interface leads

TIA-968-A

shall not trip when connected to the following tip-to-ring impedance that
terminates the off-premises station loop: A terminating impedance composed of
the parallel combination of a 15 k

Ω

resistor and an RC series circuit (resistor

and capacitor) whose ac impedance is as specified in Table 4.14.

Table 4.14

AC impedance (

Ω)

Ringing freq (Hz)

Class B or C

Class A

20 ± 3

7000/N

1400

30 ± 3

5000/N

1000

N = Number of ringer equivalences, as specified by the manufacturer, which can be
connected to the off-premises station loop.

` TIA-968-A

4.7.7 Type Z Ringers

Equipment that has on-hook impedance characteristics that do not conform to
the requirements of this section may be conditionally approved, notwithstanding
the requirements of this section and provided that it is labeled with a Ringing
Type designation ‘‘Z’’. It should be noted that approval of equipment bearing
the designation ‘‘Z’’ does not necessarily confer any right of connection to the
telephone network under these criteria. Any equipment approved with the type
Z designation may only be used with the consent of the local telephone
company, provided that the local telephone company does not discriminate in
its treatment of equipment bearing the type Z designation.

4.7.8 Transitioning to the Off-Hook State

Except as provided in 4.7.8.1 and 4.7.8.2 below, approved terminal equipment and
approved protective circuitry shall not by design leave the on-hook state by
operations performed on tip and ring leads for any other purpose than to request
service or answer an incoming call. Make-busy indications shall be transmitted by
the use of make-busy leads only as defined in section 1.3.26.

4.7.8.1 Manual programming of memory dialing numbers

Terminal equipment the user places in the off-hook state for the purpose of
manually placing telephone numbers in internal memory for subsequent automatic
or repertory dialing shall be acceptable for connection to the telephone network
provided it meets all other applicable requirements.

4.7.8.2 Automatic stutter dial tone detection

Terminal equipment that automatically goes off-hook for the purpose of checking
for stutter dial tone shall be acceptable for connection to the telephone network
provided it meets all other applicable requirements and all of the following
specifications and conditions:

a) the device performs no periodic testing for stutter dial tone;
b) the device makes an off-hook stutter dial tone check no more than once
after a subscriber completes a call, and completes the check no earlier than 4
seconds after the subscriber hangs-up;
c) the device makes an off-hook stutter dial tone check after an unanswered
call no more than once;
d) the device performs no off-hook stutter dial tone check after an
unanswered incoming call if the visual message indicator is already lit;
e) the device takes the line off-hook for no more than 2.1 seconds per stutter
dial tone check. Since the equipment cannot begin checking for stutter dial
tone until dial tone is present, this 2.1 second interval begins when dial tone
is applied to the line. If dial tone is not applied within 3 seconds, the
equipment should abandon the stutter dial tone check;
f) the device synchronizes off-hook checks when multiple stutter dial tone
detection and visual signaling devices are attached to the same line so that
only one check is made per calling event for a single line; and,
g) the device does not block dial tone to a subscriber attempting to initiate
a call as an off-hook stutter dial tone detection check is occurring.

TIA-968-A

4.8 BILLING PROTECTION

4.8.1 Call duration requirements on data equipment connected to the public switched

network, or to tie trunks, or to private lines that access the public switched network.

Approved data terminal equipment and approved protective circuitry shall
comply with the following requirements when answering an incoming call,
except in off-hook states in which the signals are transmitted and/or received
by electro-acoustic transducers only.

The preceding paragraph shall be applicable to approved terminal equipment
and approved protective circuitry employed with digital services where such
digital services are interconnected with the analog telephone network.

4.8.1.1 Approved protective circuitry.

Approved protective circuitry connected to associated

data equipment shall assure that the following signal power limitations are met for
at least the first 2 seconds after the off-hook condition is presented to the telephone
network in response to an incoming call:

4.8.1.1.1 The total power of signals that appear at the protective circuitry/telephone network

interface for delivery to the telephone network, when measured with the
appropriate loop simulator circuit or a 600 ohm termination shall be limited to -55
dBm within the voiceband ; and

4.8.1.1.2 Signals that appear at the protective circuitry-associated data equipment interface

for delivery to associated data equipment shall be limited as follows: for any
received signal power (appearing at the protective circuitry-telephone network
interface) up to 0 dBm ( within the voiceband), the power of signals delivered to
associated data equipment shall be no greater than the signal power that would
be delivered as a result of received signal power of -55 dBm.

4.8.1.2 Approved terminal equipment.

Approved terminal equipment for data applications shall assure that, when an
incoming telephone call is answered, the answering terminal equipment
prevents both transmission and reception of data for at least the first two
seconds after the answering terminal equipment transfers to the off-hook
condition. For the purpose of this requirement, a fixed sequence of signals that
is transmitted (and originated within) and/or received by the approved terminal
equipment each time it answers an incoming call shall not be considered data,
provided that such signals are for one or more of the following purposes:

a)  Disabling echo control devices,
b)  Adjusting automatic equalizers and gain controls,
c)  Establishing synchronization, or
d)  Signaling the presence and if required, the mode of operation, of the data

terminal at the remote end of a connection.

4.8.2 Voice and data equipment on-hook signal requirements for equipment connected to

` TIA-968-A

the public switched network, or to tie trunks, or to private lines that access the public
switched network.

Approved protective circuitry and approved terminal equipment shall comply
with the following:

4.8.2.1 The total power delivered into a 2-wire loop simulator circuit or into the transmit and

receive pairs of a 4-wire loop simulator or into a 600

Ω

termination (where

appropriate) in the on-hook state, by loop-start or ground-start equipment, shall not
exceed -55 dBm within the voiceband. Approved protective circuitry shall also
assure that for any input level up to 10 dB above the overload point, the power to a
2-wire loop simulator circuit or the transmit and receive pairs of a 4-wire loop
simulator circuit or into a 600

Ω

termination (where appropriate) does not exceed

the above limits.

4.8.2.2 The total power delivered into a 2-wire loop simulator circuit or into the transmit and

receive pairs of a 4-wire loop simulator circuit, in the on-hook state, by reverse
battery equipment shall not exceed -55 dBm within the voiceband, unless the
equipment is arranged to inhibit in-coming signals.

4.8.3 Voice and data equipment loop current requirements for equipment connected to the

public switched network

The loop current through approved terminal equipment or approved protective
circuitry, when connected to a 2-wire or 4-wire loop simulator circuit with the
600

Ω

resistor and 500 µF capacitor of the 2-wire loop simulator circuit or both

pairs of the 4-wire loop simulator circuit disconnected shall, for at least 5
seconds after the equipment goes to the off-hook state that would occur when
answering an incoming call:

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4.8.3.1 Be at least as great as the current obtained in the same loop simulator circuit with

minimum battery voltage and a maximum loop resistance when a 200

Ω

resistance

is connected across the tip and ring of the 2-wire loop simulator circuit or connected
across the tip/ring and tip-1/ring-1 conductors (tip and ring connected together and
tip-1 and ring-1 connected together) of the 4-wire loop simulator circuit in place of
the approved terminal equipment or approved protective circuitry; or

4.8.3.2 Not decrease by more than 25% from its maximum value attained during this 5-

second interval; unless the equipment is returned to the on-hook state during the
above 5-second interval.

4.8.3.3 The requirements of 4.8.3.1 and 4.8.3.2 shall also apply in the hold state and any

off-hook state.

4.8.4 Signaling interference requirements

4.8.4.1 The signal power delivered to the network interface by the approved terminal

equipment and from signal sources internal to approved protective circuitry in the
2450 Hz to 2750 Hz band shall be less than or equal to the power present
simultaneously in the 800 Hz to 2450 Hz band for the first 2 seconds after going to
the off-hook state.

4.8.4.2 Approved terminal equipment for connection to sub-rate or 1.544 Mbps digital

services shall not deliver digital signals to the telephone network with encoded
analog content energy in the 2450 to 2750 Hz band unless at least an equal
amount of encoded analog energy is present in the 800 to 2450 Hz band for the
first two seconds after going to the off-hook state.

4.8.5 On-hook requirements for approved subrate and 1.544Mbps digital terminal

equipment. Approved terminal equipment and approved protective circuitry shall
comply with the following:

4.8.5.1 The total power delivered to the telephone network in the on-hook state as derived

by a zero level decoder shall not exceed -55 dBm equivalent power for digital
signals within the voiceband.

4.8.5.2 Approved protective circuitry shall also assure that the power to a zero level

decoder does not exceed the above limits for any input level up to 10 dB above the
overload point.

4.8.5.3 Reverse battery interface. The total power derived within the voiceband by a zero

level decoder, in the on-hook state, by reverse battery equipment, shall not exceed
-55 dBm, unless the equipment is arranged to inhibit incoming signals.

4.8.6 Off-hook signal requirements for approved 1.544 Mbps terminal equipment

Off-hook signal requirements for approved terminal equipment connecting to
1.544 Mbps digital services. Upon entering the normal off-hook state, in
response to alerting, for sub-rate channels, approved terminal equipment shall

` TIA-968-A

continue to transmit the signaling bit sequence representing the off-hook state
for 5 seconds, unless the equipment is returned to the on-hook state during the
above 5-second interval.

4.8.7 Operating requirements for direct inward dialing.

4.8.7.1 For approved terminal equipment, the off-hook state shall be applied within 0.5

seconds of the time that:

4.8.7.1.1 The terminal equipment permits the acceptance of further digits that may be used

to route the incoming call to another destination.

4.8.7.1.2 The terminal equipment transmits signals towards the calling party, except for the

call progress tones, i.e.,

busy, reorder and audible ring, and the call is:

a)  Answered by the called, or another station;
b)  Answered by the attendant;
c)  Routed to a customer controlled or defined recorded announcement, except

for ‘‘number invalid,’’ ‘‘not in service’’ or ‘‘not assigned;’’

d) Routed to a dial prompt; or
e) Routed back to the public switched telephone network or other destination

and the call is answered. If the status of the answered call cannot be reliably
determined by the terminal equipment through means such as, detection of
answer supervision or voice energy, removal of audible ring, etc., the off-hook
state shall be applied after an interval of not more than 20 seconds from the
time of such routing. The off-hook state shall be maintained for the duration of
the call.

4.8.7.2 For approved protective circuitry:

4.8.7.2.1 Approved protective circuitry shall block transmission incoming from the network

until an off-hook signal is received from the terminal equipment.

4.8.7.2.2 Approved protective circuitry shall provide an off-hook signal within 0.5s following

the receipt of an off-hook signal from the terminal equipment and shall maintain
this off-hook signal for the duration of the call.

TIA-968-A

6 CONNECTORS

Connection of terminal equipment to the telephone network shall be made through a
connector conforming to this section or by direct attachment to wiring installed by the
provider(s) of wire line telecommunications including, but not limited to, splicing, bridging,
twisting, and soldering.

6.1 SPECIFICATIONS

6.1.1 General

The US customary units are shown in parentheses throughout this section. US customary
units were the original dimensional units used in designing the plugs and jacks shown in the
following pages. The dimensions shown without parenthesis are in SI (Systeme
Internationale) units (i.e. the International System of measurement). The SI dimensional
units are derived from the US customary units by multiplying inches by 25.4 to derive the
exact conversion in millimeters with no rounding-off of the resulting decimal value. The
number of decimal places to which the conversion is taken by adding a particular number of
zeroes to the right end of the resulting SI value, where required, is governed by the concept
that when the calculated SI dimensional unit is divided by 25.4, the resulting inches
calculation will be exactly that shown in the parenthesis (the original design dimension). The
conversion to SI force units, Newton (N), is rounded off to a number of decimal places that
will result in the calculated SI force value being within less than 1% of the original US
customary force unit value located adjacent in parenthesis (the original design value). The
rationale for this is that this will bring the force conversions to within the degree of accuracy
of the force-measuring device and avoid the carrying of an unrealistic number of decimal
places which would otherwise result from an exact conversion. The plugs and jacks
described in this section represent the standard connections to be used for connections to
the telephone network. The plug and jack designs shown are representative of generic
types, and should not be interpreted as the only designs that may be used. Design
innovation and improvement is anticipated; but for interchangeability to be maintained,
alternative designs (the “or equivalent” permitted in this standard) shall be compatible with
the plugs and jacks shown. The interface dimensions between mating plugs and jacks shall
be maintained. Hardware used to mount, protect, and enclose standard jacks is not
described. The only requirement on connecting blocks, housings, dust covers, outdoor
boxes, and the like that contain standard network jacks is that they shall accept standard
plugs with cordage. For special purpose applications, plugs may be made longer than
shown or adapted for direct use on equipment or apparatus without cordage. The sliding
modular plug used on the back of many modular wall telephone sets is an example of such
a special purpose application. It is the responsibility of the designers and manufacturers of
communication equipment who use such plugs to assure that they are compatible with the
hardware used to mount standard jacks with which they plan to interface. For the purposes
of this section, hard gold and contact performance equivalent to gold shall be determined in
accordance with the standards detailed in TIA TSB 31-B.

` TIA-968-A

Figure 6.3 6-Position Plug Mechanical Specification (continued)

NOTES to Figures 6.2 and 6.3:

1. All plugs shall be capable of meeting the requirements of the plugs

go and no-go gauges.

2. Section BB applies to any jack contact receiving slot that does not

contain a plug contact.

3. The major cordage cross section should be 2.5400 mm (0.100 in)

max. thick by 5.0800 mm (0.200 in) max. wide, with rounded
corners. It should exit the plug on the plug centerline. Other
cordage configurations are permitted but may inhibit the special
features of some network jack enclosures.

4. The standard plug length shall be 11.6840 mm (0.460 in) max.

Plugs may be made longer than standard or adapted for direct use
on special cords, adapters with out cordage, and on apparatus or
equipment subject to the limitations described in section 6.1.1.
Plugs longer than standard could inhibit the special features of
some network jack enclosures.

5. A 12.0396 mm (0.474 in) minimum tab length shall be required. A

maximum tab length should be no longer than 13.2080 mm (0.520
in). Longer tabs may be used with the same limitations as
described in Note 4.

6. To obtain maximum plug guidance when 6-position plugs are

inserted in 8-position jacks, the front plug nose should be extended
to the 2.3368 mm (0.092 in) maximum.

7. These dimensions shall apply to the location of jack contact

receiving slots. Plug contacts should be centered axially in these
slots.

` TIA-968-A

NOTES to Figure 6.4

1. The plug/jack contact interface shall be hard gold to hard gold and

shall have a minimum gold thickness of 1.2700 µm (0.050 mil) on
each side of the interface. The minimum contact force should be
0.98 N (100 g). Any non-gold contact material shall be compatible
with gold and provide equivalent contact performance. A smooth,
burr-free surface shall exist at the interface in the area shown.

2. The jack contact design is based upon 0.4572 mm (0.018 in) spring

temper phosphor bronze round wire in the modular plug blade and
jack contact interface. Other contact configurations that provide
contact performance equal to or better than the preferred
configurations and do not cause damage to the plug or jack are
permitted. The jack contact width should be 0.44958/0.49530 mm
(0.0177/0.0195 in). Deviations from the preferred jack contact width
are permitted for round contacts as well as noncircular cross
sectional shapes but they shall be compatible with existing plug
configurations. The requirements of Note 1 shall apply to all
possible contact areas.

3. The configuration of the plug contact and the front plastic of the plug

shall prevent jack contacts from being damaged during plug
insertion into jacks.

4. This nominal contact angle should be provided between plugs and

jacks with the plug latched into the jack. This angle shall be less
than 24° to avoid loss of electrical contact between the plug and
jack. The nominal contact angle shall be greater than 13° to avoid
interference between jack contacts and the internal plastic in the
plug.

5. To avoid loss of electrical contact, the dimension from datum B to

the highest point ‘‘X’’ should be 5.0800 mm (0.200 in) max. A
dimension greater than 5.3594 mm (0.211 in) could result in loss of
electrical contact between plugs and jacks. The 5.3594 mm (0.211
in) max. shall be considered an absolute maximum.

6. The 24° min. angle applies only to plugs with front plastic walls

higher than 4.8260 mm (0.190 in).

` TIA-968-A

Figure 6.6 6-Position Plug Maximum Plug Size

NOTES:

1. The plug shall be capable of insertion and latching into the gauge

with 22.24 N (5 pounds) or less insertion force. Plug latching bar
shall be depressed so as not to interfere with the plug entry. After
insertion and latching, plug shall be capable of removal, with the
latch depressed, with a removal force of 44.48 N (10 pounds) or
less applied at an advantageous angle.

2. Dimensions given to three decimal places shall be within ± 0.0508

mm (± 0.002 in).

3. Dimensions (a) and (b) shall be centrally located with respect to

9.7536 mm (0.3840 in) max. Jack opening width within ± 0.0254
mm (0.001 in).

4. Drawings shall not be scaled for external configuration.

TIA-968-A

NOTES to Figures 6.7 and 6.8:

1. Front surface projections beyond the 1.2700 mm (0.050 in) min.

shall be configured so as not to prevent finger access to the plug
release catch (Reference Figure 6.12, 6-Position Plug, Mechanical
Specifications). A catch length greater than 1.2700 mm (0.050 in)
should be used to provide greater breakout strength.

2. Surface Z need not be planar or coincident with the surface under

the plug release catch. Surface Z projections shall not prevent
insertion, latching, and unlatching of the standard 6-position plug
described in section 6.1.1.

3. The indicated plug stop surface should be used. If some other

internal feature is used as a plug stop, it shall be located so that the
axial movement of a latched plug is no greater than 1.1430 mm
(0.045 in).

4. To prevent mistargeting between the plug and jack contacts, the

jack contacts shall be completely contained in their individual
contact zones, 0.7112 mm (0.028 in) max. wide, where they extend
into the jack openings. There is no location requirement for jack
contacts below these zones 5.8420 mm (0.230 in) max., but
adequate contact separation shall be maintained to prevent
electrical breakdown. These shaded contact zones shall be
centrally located, (included all locating tolerances), about the jack
opening width 9.8806 mm (0.389 in) Ref, (Datum -W-). Contacts
located outside of these zones could result in mistargeting between
the jack and plug contacts.

5. All inside and outside corners in the plug cavity shall be 0.3810 mm

(0.015 in) radius max. unless specified.

6. These surfaces shall have 0°15’ maximum draft.

7. Relief inside the dotted areas on 3 sides of the jack opening is

permitted. The 6.8326 mm (0.269 in) Ref and 9.8806 mm (0.389 in)
Ref Gauge Requirements shall be maintained in each corner, (ref.
1.0160 mm (0.040 in) min), to assure proper plug/jack interface
guidance. There shall be a 0.8128 ± 0.1270 mm (0.032 ± 0.005)
relief on the top side (opposite plug catch) on jacks in connecting
blocks which mount and connect portable wall telephones so as to
assure interface with the special purpose sliding modular plug used
on many wall telephone sets.

8. 4.0640 mm (0.160 in) and 6.5278/6.8580 mm (0.257/0.270 in)

dimensions shall be centrally located to jack opening width -W-
within ± 0.1778 mm (± 0.007 in).

9. Minimum acceptable jack contact length. When contact guide slots

are used, the contacts shall always be contained inside the guide
slots and the contacts shall move freely in the slots so as not to
restrain plug insertion or damage jack contacts.

10. Gauge Requirements:

101

TIA-968-A

Figure 6.11 8-Position Unkeyed plug, Mechanical Specification (continued)

NOTES for Figures 6.10 and 6.11:

1. All plugs shall be capable of meeting the requirements of the plug

go and no-go gauges.

2. The standard plug height in the area shown shall be 8.0010 mm

(0.315 in) maximum. The standard plug length shall be 23.1140
mm (0.910 in) maximum. Plugs may be made longer than
standard or adapted for direct use on special cords, adapters
without cordage, apparatus or equipment subject to the limitations
described in the introductory paragraphs of section 6. Plugs
longer and/ or higher than standard could inhibit the special
features of some network jack enclosures.

3. A 14.6050 mm (0.575 in) minimum tab length shall be provided.

The maximum tab length should be no longer than 15.8750 mm
(0.625 in). Longer tabs may be used with the same limitations
described in Note 2.

4. To obtain maximum plug guidance in jacks, the front plug nose

should be extended to the 2.3368 mm (0.092 in) maximum.

5. These dimensions shall apply to the location of jack contact

receiving slots. Plug contacts should be centered axially in these
slots.

The center rib centerline shall be coincident with the plug width 11.6840 mm ref. (0.460 in
ref.) centerline within

0.0762 mm (

0.003 in).

105

TIA-968-A

permitted. Contact width should be 0.44958/0.49530 mm
(0.0177/0.0195 in). Deviations from the desirable jack contact
width are permitted for round contacts as well as noncircular cross
sectional shapes but they shall be compatible with existing plug
configurations. The requirements of Note 1 shall apply to all
possible contract areas.

3. The configuration of the plug contact and the front plastic of the

plug shall prevent jack contacts from being damaged during plug
insertion into jacks.

4. This nominal contact angle should be provided between plugs and

jacks with the plug latched into the jack. This angle shall be equal
to or less than 24° to avoid loss of electrical contact between the
plug and jack. The nominal contact angle shall be equal to or
greater than 13° to prevent interference between jack contacts
and the internal plastic in the plug.

5. To avoid loss of electrical contact, the dimension from datum B to

the highest point ‘‘X’’ should be 5.0800 mm (0.200 in) max. A
dimension greater than 5.3594 mm (0.211 in) could result in loss
of electrical contact between plugs and jacks. The 5.3594 mm
(0.211 in) max. shall be considered an absolute maximum.

6. The 24° min. angle shall apply only to plugs with front plastic walls

higher than 4.8260 mm (0.190 in).

107

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Figure 6.17 8-Position Series Jack, Mechanical Specification (continued)

NOTES to Figures 6.16 and 6.17:

1. Front surface projections beyond the 1.3970 mm (0.055 in)

minimum shall be configured so as not to prevent finger access to
the plug release catch (Reference Figure 6.2 and Figure 6.10, 6
and 8-Position Plug, Mechanical Specifications). A catch length
greater than 1.3970 mm (0.055 in) should be provided for greater
breakout strength and improved guidance when interfacing with a
6-position plug.

2. Surface Z need not be planar or coincident with the surface under

the plug release catch. Surface Z projections shall not prevent
insertion, latching, and unlatching of the standard 8-position plug
on Figure 6.10.

3. The indicated plug stop surface should be provided. If some other

internal feature is used as a plug stop, it shall be located so that

112

TIA-968-A

the axial movement of a latched plug is no greater than 1.1430
mm (0.045 in).

4. To prevent mistargeting between the plug and jack contacts, the

jack contacts shall be completely contained in their individual
contact zones, (0.7112 mm (0.028 in) max. wide), where they
extend into the jack openings. There is no location requirement
for jack contacts below these zones (5.8420 mm (0.230 in) max.),
but adequate contact separation shall be maintained to prevent
electrical breakdown. These shaded contact zones shall be
centrally located, (include all locating tolerances), about the jack
opening width 11.9126 mm (0.469 in) Ref, (Datum -W-). Contacts
located outside of these zones could result in mistargeting
between the jack and plug contacts.

5. All inside and outside corners in the plug cavity shall be 0.3810

mm (0.015 in) radius max. unless specified.

6. These surfaces shall have 0°15’ maximum draft.

7. Relief inside the dotted areas on both sides of the jack opening is

permitted. The 6.8326 mm (0.269 in) Ref and 11.9126 mm (0.469
in) Ref Gauge Requirements shall be maintained in each of the
corners indicated, (Ref. 1.5240 mm (0.060 in) min), to assure
proper plug/jack interface guidance.

8. 4.0640 mm (0.160 in) and 6.2992 mm (0.248 in) dimensions shall

be centrally located to jack opening width -W- within ± 0.1270 mm
(0.005 in).

9. The contact lengths shall be such that the contacts will always be

contained inside the guide slots, and the contacts shall move
freely in the slots so as not to restrain plug insertion or damage
jack contacts.

10. Gauge Requirements:

•

GO: The jack shall be capable of accepting an 11.7856 mm x 6.7056
mm (0.4640 in x 0.2640 in) gauge and the gauge shall be capable of
being removed with a maximum force of 8.9 N (2.0 pounds).

•

NO GO: The jack shall not accept either a 12.0396 mm x 6.4516 mm
(0.4740 in x 0.254 in) horizontal width of opening gauge or a 6.9596
mm x 11.5824 mm (0.2740 in x 0.456 in) vertical height of opening
gauge. However, if the gauge is accepted, the force necessary to
remove the gauge shall be a minimum of 0.83 N (3.0 ounces).

•

Removal force requirements do not include forces contributed by
contact springs nor shall external forces be applied to the jack that
will affect these removal forces.

•

Gauges shall have a 0.7620 mm (0.030 in) radius on the nose and a
0.3810 mm (0.015 in) radius on all edges with clearance provided for
contacts.

11. With no plug inserted, conductors 1 and 4 shall be bridged as well

as conductors 5 and 8. With a miniature 8-position plug inserted
into the jack, the bridge connectors shall be broken and a series

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connection shall be made in both sides of the line. With a 6-
position plug inserted, the bridged connections shall remain
unbroken.

12. The jack contact/bridging interface shall be hard gold to hard gold

and shall have a minimum gold thickness of 1.2700 µm (0.050 mil)
on each side of the interface. The minimum hard gold contact
bridging force shall be 0.294 N (30 g). Any non-gold contact
material shall be compatible with gold and provide equivalent
contact performance.

6.1.1.5 50-position miniature ribbon plug

6.1.1.5.1 Contact finish in the region of contact shall be gold, 0.7620 µm (0.030 mil)

minimum thickness, and should be electrodeposited hard gold.

6.1.1.5.2 ‘‘Datum B’’ shall be the center line of contact cavities.

6.1.1.5.3 The center line of each contact shall be located within 0.2286 mm (0.009 in) of

true position with respect to ‘‘Datum B’’.

6.1.1.5.4 Contact width at region of contact shall be (1.143 ± 0.0508) mm (0.04 ± 0.002 in).

6.1.1.5.5 Center line of shell dimension indicated shall be within 0.1270 mm (0.005 in) of

‘‘Datum B’’.

6.1.1.5.6 Center line of barrier dimension indicated shall be within 0.1270 mm (0.005 in) of

‘‘Datum B’’.

6.1.1.5.7 ‘‘Surface X’’ shall have a 0.1016 µm (0.004 mil) finish or better; finishing shall be

done in the direction of the arrow.

6.1.1.5.8 A force of not more than 178 N (40 pounds) shall be sufficient to fully insert the

plug onto the sizing gauge shown on Figure 6.18. The plug is fully inserted
when ‘‘Surface A’’ of the plug

touches ‘‘Surface A’’ of the sizing gauge.

6.1.1.5.9 After one insertion of the plug on the sizing gauge, Figure 6.19, a force of not

more than 44.5 N (10 pounds) shall be sufficient to fully insert the plug on the
continuity gauge shown in Figure 6.20. The plug is fully inserted on the
continuity gauge when ‘‘Surface A’’ of the plug

touches ‘‘Surface A’’ of the

continuity gauge.

6.1.1.5.10 When the plug is fully inserted on the continuity gauge, Figure 6.20, after

having been inserted once on the sizing gauge, Figure 6.19, all contacts of the
plug shall electrically contact the continuity gauge as determined by an
electrical continuity test which applies an open circuit voltage of not more than
10 Volts. Results greater than 200

Ω

indicate test failure.

Figure 6.18.

Figures 6.19 and 6.20.

114

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Figure 6.21 50-Position Miniature Ribbon Plug Hood Envelope

6.1.1.6 50-position miniature ribbon jack

6.1.1.6.1 Contact finish in the region of contact shall be gold, 0.7620 µm (0.030 mil)

minimum thickness, and should be electrodeposited hard gold.

6.1.1.6.2 ‘‘Datum B’’ shall be considered the center line of contact cavities.

6.1.1.6.3 The center line of each contact shall be located within 0.2286 mm (0.009 in) of

true position with respect to ‘‘Datum B’’.

6.1.1.6.4 Contact width at region of contact shall be 1.1430± 0.0508 mm (0.045±0.002 in).

6.1.1.6.5 Center line of shell dimension indicated shall be within 0.1270 mm (0.005 in) of

Datum B’’.

118

TIA-968-A

6.1.1.6.6 Center line of cavity dimension indicated shall be within 0.1270 mm (0.005 in) of

Datum B’’.

6.1.1.6.7 ‘‘Surface X’’ shall have a 0.1016 µm (0.004 mil) finish or better; finishing shall be

done in the direction of the arrow.

6.1.1.6.8 A force of not more than 134 N (30 pounds) shall be sufficient to fully insert the

jack onto the sizing gauge shown on Figure 6.23. The jack is fully inserted
when ‘‘Surface A’’ of the jack

touches ‘‘Surface A’’ of the sizing gauge.

6.1.1.6.9 After one insertion of the jack on the sizing gauge, Figure 6.23, a force of not

more than 44.5 N (10 pounds) shall be sufficient to fully insert the jack on the
continuity gauge shown in Figure 6.24. The jack is fully inserted on the
continuity gauge when ‘‘Surface A’’ of the jack

touches ‘‘Surface A’’ of the

continuity gauge.

6.1.1.6.10 When the jack is fully inserted on the continuity gauge, Figure 6.24, after having

been inserted once on the sizing gauge, all contacts of the jack shall electrically
contact the continuity gauge as determined by an electrical continuity test
which applies an open circuit voltage of not more than 10 volts. Results greater
than 200

Ω

indicate test failure.

Figure 6.22.

Figures 6.23 and 6.24.

119

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Figure 6.30 8-Position Keyed Plug, Mechanical Specification (continued)

NOTES to Figures 6.29 and 6.30:

1. All plugs shall meet the requirements of the plug go and no-go

gauges.

2. The standard plug height in the area shown shall be 8.0010 mm

(0.315 in) maximum. The standard plug length shall be 23.1140
mm (0.910 in) maximum. Plugs may be made longer than
standard or adapted for direct use on special cords, adapters
without cordage, apparatus or equipment subject to the limitations
described in section 6.1.1. Plugs longer and/ or higher than
standard could inhibit the special features of some network jack
enclosures.

3. The minimum tab length shall be 14.6050 mm (0.575 in). The

maximum tab length normally shall be no longer than 15.8750 mm
(0.625 in). Longer tabs may be used with the limitations described
in Note 2.

4. To obtain maximum plug guidance in jacks, the front plug nose

should be extended to the 2.3368 mm (0.092 in) maximum.

5. These dimensions apply to the location of jack contact receiving

slots. Plug contacts should be centered axially in these slots.

6. The center rib centerline shall be coincident with the plug width,

11.6840 mm ref (0.460 in ref.) center line within ± 0.0762mm (±
0.003 in)

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` TIA-968-A

NOTES to Figure 6.31:

1. The plug/jack contact interface shall be hard gold to hard gold and

shall have a minimum gold thickness of 1.2700 µm (0.050 mil) on
each side of the interface. The minimum contact force shall be
0.98 N (100 g). Any non-gold contact material shall be compatible
with gold and provide equivalent contact performance. A smooth,
burr-free surface shall exist at the inter-face in the area shown.

2. The jack contact design is based upon 0.4572 mm (0.018 in)

spring temper phosphor bronze round wire in the modular plug
blade and jack contact interface. Other contact configurations that
provide contact performance equal to or better than the preferred
configurations and do not cause damage to the plug or jack may
be provided. The jack contact width normally shall be
0.44958/0.49530 mm (0.0177/0.0195 in). Deviations from the
preferred jack contact width are permitted for round contacts as
well as noncircular cross sectional shapes but such deviations
shall be compatible with existing plug configurations. The
requirements of Note 1 shall apply to all possible contact areas.

3. The configuration of the plug contact and the front plastic of the

plug shall prevent jack contacts from being damaged during plug
insertion into jacks.

4. This should be the nominal contact angle between plugs and jacks

with the plug latched into the jack. This angle shall be equal to or
less than 24° to avoid loss of electrical contact between the plug
and jack. The nominal contact angle shall be equal to or greater
than 13° to avoid interference between jack contacts and the
internal plastic in the plug.

5. To avoid loss of electrical contact, the dimension from “Datum B”

to the highest point “X” should be 5.0800 mm (0.200 in) max. A
dimension greater than 5.3594 mm (0.211 in) could result in loss
of electrical contact between plugs and jacks. The 5.3594 mm
(0.211 in) max. shall be considered an absolute maximum.

6. The 25° min. angle shall apply only to plugs with front plastic walls

higher than 4.8260 mm (0.190 in).

130

TIA-968-A

Figure 6.32 8-Position Keyed Plug, Maximum Plug Size

NOTES:

1. The plug shall be capable of insertion and latching into the gauge

2. Dimensions given to four decimal places shall be within ± 0.0508

mm (± 0.002 in).

3. Dimensions (a) and (b) shall be centrally located with respect to

11.7856 mm (0.4640 in) max. Jack opening width shall be within
± 0.0254 mm (± 0.001 in).

4. Drawings shall not be scaled for external configuration.

131

` TIA-968-A

Figure 6.35 8-Position Keyed Jack, Mechanical Specification

NOTES to Figure 6.35:

1. Front surface projections beyond the 1.3970 mm (0.055 in)

minimum shall be configured so as not to prevent finger access to
the plug release catch (Reference Figure 6.30 and 8-Position
Plug, Mechanical Specifications). A catch length should be
greater than 1.3970 mm (0.055 in) to provide greater breakout
strength and improved guidance when interfacing with a 6-position
plug.

2. Surface Z need not be planar or coincident with the surface under

the plug release catch. Surface Z projections shall not prevent
insertion, latching, and unlatching of the standard 8-position plug
on Figure 6.29.

3. The indicated plug stop surface should be provided. If some other

internal feature is used as a plug stop, it shall be located so that
the axial movement of a latched plug is no greater than 1.1430

134

TIA-968-A

mm (0.045) in.

4. To prevent mistargeting between the plug and jack contacts, the

jack contacts shall be completely contained in their individual
contact zones 0.7112 mm (0.028 in) max wide, where they extend
into the jack openings. There is no location requirement for jack
contacts below these zones (5.8420 mm (0.230 in) max), but
adequate contact separation shall be maintained to prevent
electrical breakdown. These shaded contact zones shall be
centrally located, (include all locating tolerances), about the jack
opening width 11.9126 mm (0.469 in) Ref, (Datum–W–). Contacts
located outside of these zones could result in mistargeting
between the jack and plug contacts.

5. All inside and outside corners in the plug cavity shall be 0.3810

mm (0.015 in) radius max unless specified.

6. These surfaces shall have 0°15' maximum draft.

7. Relief inside the dotted areas on both sides of the jack opening

shall be permitted. The 6.8326 mm (0.269 in) Ref and 11.9126
mm (0.469 in) Ref Gauge Requirements shall be maintained in
each of the corners indicated, (Ref. 1.5240 mm (0.060 in) min), to
assure proper plug/jack interface guidance.

8. 4.0640 mm (0.160 in) and 6.2992 mm (0.248 in) dimensions shall

be centrally located to jack opening width –W– within ± 0.1270
mm (± 0.005 in).

9. The contact lengths shall be such that the contacts will always be

contained inside the guide slots and the contacts shall move freely
in the slots so as not to restrain plug insertion or damage jack
contacts.

10. Gauge Requirements:

•

GO: The jack shall be capable of accepting an 11.78560 x 6.70560 mm
(0.4640 x 0.2640 in) gauge and the gauge shall be capable of being
removed with a maximum force of 8.9 N (2.0 pounds).

•

NO GO: The jack shall not accept either a 12.03960 x 6.4516 mm
(0.4740 x 0.254 in) horizontal width of opening gauge or a 6.95960 x
11.5824 mm (0.2740 x 0.456 in) vertical height of opening gauge.
However, if the gauge is accepted, the force necessary to remove the
gauge shall be a minimum of 0.83 N (3.0 ounces).

•

Removal forces shall not include forces contributed by contact springs
nor shall external forces be applied to the jack that will affect these
removal forces.

•

Gauges shall have a 0.7620 mm (0.030 in) radius on the nose and a
0.3810 mm (0.015 in) radius on all edges with clearance provided for
contracts.

135

` TIA-968-A

6.2 WIRING CONFIGURATIONS

The connectors specified in this standard shall be wired in accordance with any of the
applicable wiring configurations provided in T1.TR.5-1999. The applicable connector and
connector wiring configuration for approved TE shall be identified in consumer instructions
and product approval documentation.

6.2.1 Universal Service Ordering Code

A Universal Service Ordering Code (USOC) is specified in T1.TR5-1999 for each wiring
configuration. These USOCs are generic service ordering codes that are used or recognized
by most wireline carriers. If a customer wishes to have the wireline carrier install a jack or
wiring configuration, the appropriate USOC needs to be specified when the customer
requests service installation.

6.2.2 Default Connector Wiring Configuration

In the absence of a request for a specific type of jack and wiring configuration, wireline
carriers will typically install a 6-position non-keyed jack with the RJ11W (for wall mounted
equipment) or RJ11C (for all other equipment) wiring configuration shown in Figure 6-36.

Jack

Network

Plug

from

Customer

Installation

R
T

Figure 6-36 – RJ11C/W Network Interface Wiring Configuration

136

6.3 CONFIGURATIONS USED TO CONNECT MULTI-LINE

COMMUNICATIONS SYSTEMS SUCH AS PRIVATE BRANCH
EXCHANGE (PBX) AND KEY TELEPHONE SYSTEMS

Any of the jack configurations specified in section 6.2, used singly, in multiple combinations,
or combined in common mechanical arrays, may be used as the interface between multi-line
equipment such as PBX and key telephone systems, and the telephone network. The
telephone company and installation supervisor may mutually agree to use electrical

TIA-968-A

Annex A (normative)

Grandfathered Terminal Equipment

(normative)

A.1 Introduction

This annex identifies terminal equipment (TE) that has been grandfathered by FCC action
and identifies the conditions under which such TE may be connected to the public switched
telephone network and services without approval.

A.2 Grandfathered terminal equipment (other than PBX and key telephone systems)
and protective circuitry.

All terminal equipment (other than PBX and key telephone systems) and protective circuitry
of a type directly connected to the public switched telephone network and services identified
in 1.1(b) as of October 17, 1977, may be connected thereafter up to July 1, 1979—and may
remain connected for life—without approval unless subsequently modified.

A.3 Grandfathered systems (including, but not limited to, PBX and key telephone
systems).

a) Entire systems, including their equipment, premises wiring, and protective

apparatus (if any) directly connected to the public switched telephone
network and services identified in 1.1(b) on June 1, 1978, may remain
connected to the public switched telephone network and services identified in
1.1(b) for life without approval, unless subsequently modified, except for
modifications allowed under A.3(c).

b) New installations of equipments may be performed (including additions to

existing systems) up to January 1, 1980, without approval of any equipments
involved, provided that these equipments are of a type directly connected to
the public switched telephone network or services identified in 1.1(b) as of
June 1, 1978. These equipments may remain connected to the public
switched telephone network or services identified in 1.1(b) for life without
approval, unless subsequently modified, except for modifications allowed
under A.3(c).

c) Modifications to systems and installations involving unapproved equipment:

1) Use of other than fully-protected premises wiring is a modification under

1.1. As an exception to the general requirement that no modification is
permitted to unapproved equipment whose use is permitted under 1.1,
certain modifications are authorized here-in.

2) Other than fully-protected premises wiring may be used if it is qualified in

accordance with the procedures and requirements of § 68.215. Since there
is no ‘‘responsible party’’ of unapproved equipment, the training and
authority required by § 68.215(c) will have to be received from the
equipment’s manufacturer.

139

` TIA-968-A

3) Existing separate, identifiable and discrete protective apparatus may be

removed, or replaced with apparatus of lesser protective function, provided
that any premises wiring to which the public switched telephone network or
service identified in 1.1 is there-by exposed conforms to A.3(c)(2) above.
Minor modifications to existing unapproved equipments are authorized to
facilitate installation or premises wiring, so long as they are performed
under the responsible supervision and control of a person who complies
with § 68.215(c). Since there is no ‘‘responsible party’’ of unapproved
equipment, the training and authority required by § 68.215(c) will have to be
received from the manufacturer of the equipment so modified.

A.4 Grandfathered private branch exchange (or similar) systems for connection to
private line type services (tie trunk type services, off-premises station lines,
automatic identified outward dialing, and message registration):

a) PBX (or similar) systems, including their equipments, premises wiring, and

protective apparatus (if any) directly connected to a private line type service
on April 30, 1980 may remain connected to the private line type service for
life without approval unless subsequently modified, except for modifications
allowed under A.4(c).

b) New installations of equipments may be performed (including additions to

existing systems) up to May 1, 1983 without approval of any equipments
involved, provided that these equipments are of a type directly connected to a
private line type service as of April 30, 1980. These equipments may remain
connected to the private line type service for life without approval, unless
subsequently modified, except for modifications allowed under A.4(c).

c) Modifications to systems and installations involving unapproved equipment:

1) Use of other than fully-protected premises wiring is a modification

under 1.1. As an exception to the general requirement that no
modification is permitted to unapproved equipment whose use is
permitted under 1.1, certain modifications are authorized here-in.

2) Other than fully-protected premises wiring may be used if it is

qualified in accordance with the procedures and requirements of §
68.215. Since there is no ‘‘responsible party’’ of unapproved
equipment, the training and authority required by § 68.215(c) will
have to be received from the equipment’s manufacturer.

Existing separate, identifiable and discrete protective apparatus may
be removed, or replaced with apparatus of lesser protective
function, provided that any premises wiring to which the private line
type service is thereby exposed conforms to A.4(c)(2) above. Minor
modifications to existing unapproved equipments are authorized to
facilitate installation or premises wiring, so long as they are
performed under the responsible supervision and control of a
person who complies with § 68.215(c). Since there is no
‘‘responsible party’ of unapproved equipment, the training and
authority required by § 68.215(c) will have to be received from the
manufacturer of the equipment so modified.

140

TIA-968-A

d) PBX (or similar) systems connected with automatic identified outward dialing

or message registered private line services of a type that complies with
paragraphs A.4(3)(a) and A.4.(3)(b) of this section may remain connected for
life without approval unless subsequently modified.

A.5 Grandfathered terminal equipment for connection to local area data channels.

All terminal equipment of a type directly connected to Local Area Data Channels or directly
connected under special assembly tariff provisions to telephone company-supplied, non-
loaded, metallic, greater-than-voiceband circuits for the purpose of providing limited distance
data transmission as of February 10, 1986, may be connected thereafter up to August, 10,
1987, and may remain connected for life, without approval unless subsequently modified.

A.6 Grandfathered terminal equipment for connection to subrate and 1.544 Mbps
digital services.

a) Terminal equipment including premises wiring and protective apparatus (if

any) directly connected to subrate or to 1.544 Mbps digital services on
January 2, 1986, may remain connected and be reconnected to such digital
services for life without approval, unless subsequently modified.

b) New installations of terminal equipments, including premises wiring and

protective apparatus (if any) may be installed including additions to existing
systems) up to June 30, 1987, without approval of any terminal equipment
involved, provided that these terminal equipments are of a type directly
connected to subrate or 1.544 Mbps digital services as of January 2, 1986.
These terminal equipments may remain connected and be reconnected to
such digital services for life without approval, unless subsequently modified.

A.7 Grandfathered test equipment.

a) Test equipment directly connected to the telephone network on February 10,

1986, is considered to be grandfathered and may remain connected to the
telephone network for life without approval unless subsequently modified.

b) New installations of test equipment may be performed up to August 10, 1987

without approval, provided that the test equipment is of a type directly
connected to the public switched network or services identified in 1.1(a), (b),
(c), (d), (e), and (f) for life without approval unless subsequently modified.

A.8 Grandfathered terminal equipment or systems for connection to voiceband
private line channels for 2-point and multipoint private line services that utilize loop
start, ringdown, or inband signaling; or voiceband metallic channels.

a) Terminal equipment or systems, including premises wiring and protective

apparatus (if any), directly connected to voiceband private lines for 2-point or
multipoint service on February 10, 1986, may remain connected to that
private line type service for life without approval unless subsequently
modified, except for modifications allowed under A.8(c).

141

` TIA-968-A

b) New installations of equipments may be installed (including additions to

existing systems) up to August 10, 1987 without approval of any equipments
involved, provided that these equipments are of a type directly connected to
voiceband private lines for 2-point or multipoint services. These equipments
may remain connected to the private line-type service for life without
approval, unless subsequently modified, except for modifications allowed
under A.8(c).

c) Modification to systems and installations involving unapproved equipment:

1) Use of other than fully-protected premises wiring is a modification under

1.1. As an exception to the general requirements that no modification is
permitted to unapproved equipment whose use is permitted under 1.1,
certain modifications are authorized here-in.

2) Other than fully-protected premises wiring may be used if it is qualified in

accordance with procedures and requirements of § 68.215. Since there is
no ‘‘responsible party’’ of unapproved equipment, the training and authority
required by § 68.215(c) will have to be received from the equipment’s
manufacturer.

Existing separate, identifiable, and discrete protective apparatus may be

removed or replaced with apparatus of lesser protective function, provided
that any premises wiring to which the private line service is thereby
exposed conforms to A.8(c)(2) of this section. Minor modifications to
existing unapproved equipments are authorized to facilitate installation of
premises wiring, so long as they are performed under the responsible
supervision and control of a person who complies with § 68.215(c). Since
there is no ‘‘responsible party’’ of unapproved equipment, the training and
authority required by §68.215(c) will have to be received from the
manufacturer of the equipment so modified.

A.9 Terminal equipment, including its premises wiring directly connected to PSDS
(Type I, II or III)

a) Terminal equipment, including its premises wiring directly connected to PSDS

(Type I, II or III) on or before November 13, 1996, may remain for service life
without approval, unless subsequently modified. Service life means the life of
the equipment until retired from service. Modification means changes to the
equipment that affect compliance with technical criteria in this standard or 47
CFR Part 68 rules.

b) New installation of terminal equipment, including its premises wiring, may

occur until May 13, 1998, without approval of any terminal equipment
involved, provided that the terminal equipment is of a type directly connected
to PSDS (Type I, II or III) as of November 13, 1996. This terminal equipment
may remain connected and be reconnected to PSDS (Type I, II or III) for
service life without approval unless subsequently modified.

c) Terminal equipment including premises wiring and protective apparatus (if

any) directly connected to the network on April 20, 1998, may remain
connected and be reconnected for life without approval, unless subsequently
modified. New installations of terminal equipment, including premises wiring

142

TIA-968-A

and protective apparatus (if any) may be installed (including additions to
existing systems) up to May 19, 1999, without approval of any terminal
equipment involved, provided that the terminal equipment is of a type directly
connected to the network as of April 20, 1998. This terminal equipment may
remain connected and be reconnected to the network for life without
approval, unless subsequently modified.

A.10 Terminal equipment, including premises wiring directly connected to ISDN BRA
or PRA

a) Terminal equipment, including premises wiring directly connected to ISDN

BRA or PRA on November 13, 1996, may remain connected to ISDN BRA or
PRA for service life without approval, unless subsequently modified.

b) New installation of terminal equipment, including premises wiring, may occur

until May 13, 1998, without approval of any terminal equipment involved,
provided that the terminal equipment is of a type directly connected to ISDN
BRA or PRA as of November 13, 1996. This terminal equipment may remain
connected and be reconnected to ISDN BRA or PRA for service life without
approval unless subsequently modified.

A.11 Grandfathered central office implemented payphone equipment.

a) Terminal equipment, including its premises wiring, that is directly connected

to a central-office-implemented telephone line on or before October 8, 1997,
may remain for service life without approval, unless subsequently modified.
Service life means that life of the equipment until retired from service.
Modification means changes to the equipment that affect the part 68-related
characteristics of that equipment at the network interface.

b) New installation of terminal equipment, including its premises wiring, may

occur until April 8, 1999, without approval of any central-office-implemented
telephone line equipment involved, provided that the terminal equipment is of
a type directly connected to a central-office-implemented telephone line as of
October 8,1997. This terminal equipment may remain connected and be
reconnected to a central-office-implemented telephone line.

143

` TIA-968-A

Annex B (informative)

Cross-Reference to 47 CFR Part 68

This annex provides a cross-referenced index between 47 CFR Part 68 (October 2000), 47
CFR Part 68 (February 2001), and this Standard.

Table A.1 Cross-Reference to Body Text

47 CFR Part 68

(October 2000)

47 CFR Part 68

(February 2001)

TIA-968

Subpart A – General.

Subpart A - General.

68.1 Purpose.

68.1 (no change)

1.1 Scope

68.2 Scope.

(7) 68.2 (revised) Scope.

1.2 Normative References

68.3 Definitions.

(8) 68.3 (revised)
Definitions.

1.3 Definitions

68.4 Hearing aid-compatible
telephones.

68.4 (no change).

68.5 Waivers.

68.5 (no change).

68.6 Telephones with
volume control.

68.6 (no change).

(9) 68.7 (added) Technical
criteria for terminal
equipment.

Subpart B. Conditions on
Use of Terminal Equipment.

Subpart B.

2.0 Conditions on Use

68.100 General.

(10) 68.100 (revised)
General.

68.102 Registration
requirements.

(11) 68.102 (revised)
Terminal equipment
approval requirement.

68.104 Means of
connection.

(12) Removed.

(13) 68.105 (added)
Minimum point of entry
(MPOE) and demarcation
point.

68.106 Notification to
telephone company.

(14) 68.106 (revised)
Notification to provider of
wireline

144

TIA-968-A

47 CFR Part 68

(October 2000)

47 CFR Part 68

(February 2001)

TIA-968

telecommunications.

68.108 Incidence of harm.

(15) 68.108 (introductory
text amended) Incidence of
harm.

68.110 Compatibility of the
telephone network and
terminal equipment.

(16) 68.110 (revised)
Compatibility of the public
switched telephone network
and terminal equipment.

68.112 Hearing aid-
compatibility.

68.112 (no change).

68.160 Designation of
Telecommunication
Certification Bodies.

68.160 (no change).

68.162 Requirements for
Telecommunication
Certification Bodies.

68.162 (no change).

Subpart C – Registration
Procedures..

(17 – change in title)
Subpart C – Terminal
Equipment Approval
Procedures.

3.0 Procedures

68.200 Application for
equipment registration.

(18) Removed.

(19) 68.201 (added)
Connection to the public
switched telephone network.

68.202 Public notice.

(20) Removed.

68.204 Comments and
replies.

(20) Removed.

68.206 Grant of application.

(20) Removed.

68.208 Dismissal and return
of application.

(20) Removed.

68.210 Denial of application. (20) Removed.

68.211 Registration
revocation procedures.

(21) 68.211 (revised)
Terminal equipment
approval revocation
procedures.

68.212 Assignment of
equipment registration.

(22) Removed.

145

` TIA-968-A

47 CFR Part 68

(October 2000)

47 CFR Part 68

(February 2001)

TIA-968

68.213 Installation of other
than “fully protected” non-
system simple customer
premises wiring.

68.213 ((23) (b) - revised)
Installation of other than
“fully protected” non-system
simple customer premises
wiring.

68.214 Changes in
registered equipment and
circuitry.

(24) 68.214 (revised)
Changes in other than “fully
protected” premises wiring
that serves fewer than four
subscriber access lines.

68.215 Installation of other
than “fully protected” system
premises wiring that serves
more than four subscriber
access lines.

(25) 68.215 (amended)
Installation of other than
“fully protected” system
premises wiring that serves
more than four subscriber
access lines.

(25) Revised 68.215(a)(2),
(a)(3), the first sentence of
(d)(5), (e)(9), (g)(1) through
(5), and by removing the
note after (d)(2).

68.216 Repair of registered
terminal equipment and
registered protective
circuitry.

(26) Removed.

68.218 Responsibility of
grantee of equipment
registration.

(27) 68.218 (revised)
Responsibility of the party
acquiring equipment
authorization.

68.220 Cross reference.

(28) Removed.

68.224 notice of non-
hearing aid compatibility.

68.224 (no change).

68.226 Registration of digital
systems components.

(29) Removed.

Subpart D – Conditions for
Registration.

(30 – heading revised)
Subpart D, Conditions for
Terminal Equipment
Approval.

4.0 Tech Rqmts.

68.300 Labeling
requirements.

(31) 68.300 (amended)
Approval of terminal

4.1 Labeling

146

TIA-968-A

47 CFR Part 68

(October 2000)

47 CFR Part 68

(February 2001)

TIA-968

equipment for connection to
the public switched network.

(31) revised 68.300(a),
removed (b), redesignated
(c) as (b).

68.302 Environmental
simulation.

(32) Removed.

4.2 Environmental Sim.

68.304 Leakage current
limitation.

(32) Removed.

4.3 Leakage Current Lim.

68.306 Hazardous voltage
limitations.

(32) Removed.

4.4 Hazardous Voltage Lim.

68.308 Signal power
limitations.

(32) Removed.

4.5 Signal Power Lim.

68.310 Transverse balance
limitations.

(32) Removed.

4.6 Transverse Bal. Lim.

68.312 On-hook impedance
limitations.

(32) Removed.

4.7 On-Hook Z Lim.

68.314 Billing protection.

(32) Removed.

4.8 Billing Protection

68.316 Hearing aid
compatibility: Technical
requirements.

68.316 (no change).

68.317 Hearing aid
compatibility volume control:
technical standards.

68.317 (no change).

68.318 Additional
limitations.

68.318 (no change).

(33) 68.320 (added)
Supplier’s Declaration of
Conformity.

(34) 68.321 (added)
Location of responsible
party.

(35) 68.322 (added)
Changes in name, address,
ownership or control of
responsible party.

(36) 68.324 (added)
Supplier’s Declaration of
Conformity requirements.

147

` TIA-968-A

47 CFR Part 68

(October 2000)

47 CFR Part 68

(February 2001)

TIA-968

(37) 68.326 (added)
Retention of records.

(38) 68.346 (added)
Description of testing
facilities.

(39) 68.348 (added)
Changes in equipment and
circuitry subject to a
Supplier’s Declaration of
Conformity.

(40) 68.350 (added)
Revocation of Supplier’s
Declaration of Conformity.

(41) 68.354 (added)
Numbering and labeling
requirements for terminal
equipment.

Subpart E - Complaint
Procedures.

Subpart E, Complaint
Procedures.

5.0 Complaints.

68.400 Content.

(No change)

68.402 Amended
complaints.

(No change)

68.404 Number of copies.

(No change)

68.406 Service.

(No change)

68.408 Answers to
complaints and amended
complaints.

(No change)

68.410 Replies to answers
or amended answers.

(No change)

68.412 Defective pleadings. (No change)

68.414 Hearing aid-
compatibility: Enforcement.

(No change)

(42) 68.415 (added) Hearing
aid-compatibility and volume
control informal complaints.

(43) 68.417 (added)
Informal complaints, form
and content.

148

TIA-968-A

47 CFR Part 68

(October 2000)

47 CFR Part 68

(February 2001)

TIA-968

(44) 68.418 (added)
Procedure; designation of
agents for service.

(45) 68.419 (added)
Answers to informal
complaints.

(46) 68.420 (added) Review
and disposition of informal
complaints.

(47) 68.423 (added) Actions
by the Commission on its
own motion.

Subpart F – Connectors.

(48) Removed.

6.0 Connectors.

68.500 Specifications.

6.1 Specifications.

68.502 Configurations.

6.2 Configurations.

68.504 Universal patent
license agreement.

6.3 Universal patent license
agreement.

68.506 Configurations used
to connect multi-line
communications systems
such as Private Branch
Exchange (PBX) and key
telephone systems.

6.4 Configurations used to
connect multi-line
communications systems
such as Private Branch
Exchange (PBX) and key
telephone systems.

(49) Subpart G (added)
Administrative Council for
Terminal Attachments.

68.602 Sponsor of the
Administrative Council for
Terminal Attachments.

68.604 Requirements for
submitting technical criteria.

68.608 Publication of
technical criteria.

68.610 Database of terminal
equipment.

68.612 Labels on terminal
equipment.

68.614 Oppositions and
appeals.

149

TIA-968-A

Table A.2 Cross-Reference to Figures

47 CFR Part 68

(Pre-Report & Order, CC

Docket 99-216)

47 CFR Part 68

(Post-Report & Order, CC

Docket 99-216)

TIA-968

68.3(a) (Removed) 1.1

68.3(b)

(Removed)

1.2

68.3(c)

(Removed)

1.3

68.3(d)

(Removed)

1.4

68.3(e)(i)

(Removed)

1.5

68.3(e)(i)

(Removed)

1.6

68.3(f)

(Removed)

1.7

68.3(g)

(Removed)

1.8

68.3(h)

(Removed)

1.9

68.3(i)

(Removed)

1.10

68.3(j)

(Removed)

1.11

68.3(k)

(Removed)

1.12

68.302(a)

(Removed)

4.1

68.302(b)

(Removed)

4.2

68.302(c)

(Removed)

4.3

68.306(a)

(Removed)

4.4

68.308(a)

(Removed)

4.5

68.308(b)

(Removed)

4.6

68.310-1(a)

(Removed)

4.7

68.310-1(b)

(Removed)

4.8

68.310(c)

(Removed)

4.9

68.310(d)

(Removed)

4.10

68.310(e)

(Removed)

4.11

68.310(f)

(Removed)

4.12

68.500(a)(1)(i)

(Removed)

6.1

68.500(a)(2)(i)

(Removed)

6.2

68.500(a)(1)(ii)

(Removed)

6.3

68.500(a)(3)(i)

(Removed)

6.4

151

` TIA-968-A

47 CFR Part 68

(Pre-Report & Order, CC

Docket 99-216)

47 CFR Part 68

(Post-Report & Order, CC

Docket 99-216)

TIA-968

68.500(a)(4)(i) (Removed)

6.5

68.500(a)(5)(i)

(Removed)

6.6

68.500(b)(2)(i) (Removed)

6.7

68.500(b)(3)(i) (Removed)

6.8

68.500(c)(1)(i) (Removed)

6.9

68.500(c)(2)(i) (Removed)

6.10

68.500(c)(2)(ii) (Removed)

6.11

68.500(c)(3)(i) (Removed)

6.12

68.500(c)(4)(i) (Removed)

6.13

68.500(c)(5)(i) (Removed)

6.14

68.500(d)(3) (Removed)

6.15

68.500(d)(2)(i) (Removed)

6.16

68.500(d)(3)(i) (Removed)

6.17

68.500(e)(1) (Removed)

6.18

68.500(e)(2) (Removed)

6.19

68.500(e)(3) (Removed)

6.20

68.500(e)(4) (Removed)

6.21

68.500(f)(1) (Removed)

6.22

68.500(f)(2) (Removed)

6.23

68.500(f)(3) (Removed)

6.24

68.500(g)(1) (Removed)

6.25

68.500(g)(2) (Removed)

6.26

68.500(h) (Removed) 6.27

68.500(i)(1)(i) (Removed)

6.28

68.500(i)(2)(i) (Removed)

6.29

68.500(i)(2)(ii) (Removed)

6.30

68.500(i)(3)(i) (Removed)

6.31

68.500(i)(4)(i) (Removed)

6.32

68.500(i)(5)(i) (Removed)

6.33

68.500(j)(1) (Removed)

6.34

152

` TIA-968-A

Table A.3 Cross-Reference to Tables

47 CFR Part 68

(Pre-Report & Order, CC

Docket 99-216)

47 CFR Part 68

(Post-Report & Order, CC

Docket 99-216)

TIA-968

68.304(a) (Removed) 4.1

68.306(a)

(Removed)

4.2

68.306(b)

(Removed)

4.3

68.306(c)

(Removed)

4.4

68.308(a)

(Removed)

4.5

68.308(b)

(Removed)

4.6

68.308(c)

(Removed)

4.7

68.308(d)

(Removed)

4.8

68.308(e)

(Removed)

4.9

68.310(a)

(Removed)

4.10

68.310(b)

(Removed)

4.11

68.312(a)

(Removed)

4.12

68.312(b)

(Removed)

4.13

154

TIA-968-A

Annex C (informative)

Informative Definitions

The following definitions are found in the 47 CFR Part 68, Subpart A, and are provided
below as reference:

C.1.

Demarcation point (also point of interconnection):

As used in this part, the point

of demarcation and/or interconnection between the communications facilities of a
provider of wireline telecommunications, and terminal equipment, protective
apparatus or wiring at a subscriber’s premises.

C.2.

Essential telephones:

Only coin-operated telephones, telephones provided for

emergency use, and other telephones frequently needed for use by persons using
such hearing aids.

C.3.

Harm:

Electrical hazards to the personnel of providers of wireline

telecommunications, damage to the equipment of providers of wireline
telecommunications, malfunction of the billing equipment of providers of wireline
telecommunications, and degradation of service to persons other than the user of the
subject terminal equipment, his calling or called party.

C.4.

Hearing aid compatible:

Except as used at 47 CFR Part 68.4(a)(3) and 68.414, the

terms hearing aid compatible or hearing aid compatibility are used as defined in
68.316, unless it is specifically stated that hearing aid compatibility volume control,
as defined in 68.317, is intended or is included in the definition.

C.5.

Inside wiring or premises wiring:

Customer-owned or controlled wire on the

subscriber’s side of the demarcation point.

C.6.

Premises:

As used herein, generally a dwelling unit, other building or a legal unit of

real property such as a lot on which a dwelling unit is located, as determined by the
provider of telecommunications service’s reasonable and nondiscriminatory standard
operating practices.

C.6.1

Non-system premises wiring:

Wiring that is used with up to four-line business and

residence services, located at the subscriber’s premises.

C.6.2

Fully protected non-system premises wiring:

Non-system premises wiring which

is electrically behind approved (or grandfathered) equipment or protective circuitry
that assures that electrical contact between the wiring and commercial power wiring
or earth ground will not result in hazardous voltages at the telephone network
interface.

C.6.3

Unprotected non-system premises wiring:

All other non-system premises wiring.

C.7.

Private radio services:

Private land mobile radio services and other

communications services characterized by the Commission in its rules as private

157

` TIA-968-A

radio services.

C.8.

Responsible party:

The party or parties responsible for the compliance of terminal

equipment or protective circuitry intended for connection directly to the public
switched telephone network with the applicable rules and regulations in this part and
with the technical criteria published by the Administrative Council for Terminal
Attachments. If a Telecommunications Certification Body certifies the terminal
equipment, the responsible party is the holder of the certificate for that equipment. If
the terminal equipment is the subject of a Supplier’s Declaration of Conformity, the
responsible party shall be: the manufacturer of the terminal equipment, or the
manufacturer of protective circuitry that is marketed for use with terminal equipment
that is not to be connected directly to the network, or if the equipment is imported,
the importer, or if the terminal equipment is assembled from individual component
parts, the assembler. If the equipment is modified by any party not working under the
authority of the responsible party, the party performing the modifications, if located
within the U.S., or the importer, if the equipment is imported subsequent to the
modifications, becomes the new responsible party. Retailers or original equipment
manufacturers may enter into an agreement with the assembler or importer to
assume the responsibilities to ensure compliance of the terminal equipment and to
become the responsible party.

C.9.

Secure telephones:

Telephones that are approved by the United States

Government for the transmission of classified or sensitive voice communications.

C.10.

Terminal equipment:

As used in this part, communications equipment located on

customer premises at the end of a communications link, used to permit the stations
involved to provide telecommunications or information services.

158

TIA-968-A

Annex D (informative)

Informative Definitions

The following definitions previously were in 47 CFR 68.3.

D.1.

The following definitions were subdefinitions of “Demarcation Point” (see Annex C).

D.1.1.

Single-unit installations:

For single unit installations existing as of August 13, 1990,

and installations installed after that date the demarcation point shall be a point within
30 cm (12 in) of the protector or, where there is no protector, within 30 cm (12 in) of
where the telephone wire enters the customer’s premises, or as close thereto as
practicable.

D.1.2.

Multiunit installations:

a) In multiunit premises existing as of August 13, 1990, the demarcation point shall be

determined in accordance with the local carrier’s reasonable and non-discriminatory
standard operating practices. Provided, however, that where there are multiple
demarcation points within the multiunit premises, a demarcation point for a customer
shall not be further inside the customer’s premises than a point twelve in from where
the wiring enters the customer’s premises, or as close thereto as practicable.

b) In multiunit premises in which wiring is installed after August 13, 1990, including

major additions or rearrangements of wiring existing prior to that date, the telephone
company may establish a reasonable and nondiscriminatory practice of placing the
demarcation point at the minimum point of entry. If the telephone company does not
elect to establish a practice of placing the demarcation point at the minimum point of
entry, the multiunit premises owner shall determine the location of the demarcation
point or points. The multiunit premises owner shall determine whether there shall be
a single demarcation point location for all customers or separate such locations for
each customer. Provided, however, that where there are multiple demarcation points
within the multiunit premises, a demarcation point for a customer shall not be further
inside the customer’s premises than a point 30 cm (12 in) from where the wiring
enters the customer’s premises, or as close thereto as practicable.

c) In multiunit premises with more than one customer, the premises owner may adopt a

policy restricting a customer’s access to wiring on the premises to only that wiring
located in the customer’s individual unit that serves only that particular customer.

D.2.

The following definitions were subdefinitions of Inside (premises) wiring.

D.2.1.

System premises wiring:

Wiring which connects separately housed equipment

entities or system components to one another, or wiring which connects an
equipment entity or system component with the telephone network interface, located
at the customer’s premises and not within an equipment housing.

D.2.2.

Fully protected systems premises wiring:

Premises wiring that is either: No

greater than 15 m (50 feet) in length (measured linearly between the points where it

159

` TIA-968-A

leaves equipment or connector housings) and approved as a component of and
supplied to the user with the approved terminal equipment or protective circuitry with
which it is to be used. Such wiring shall either be pre-connected to the equipment or
circuitry, or may be so connected by the user (or others) if it is demonstrated in the
approval application that such connection by the untrained will not result in harm,
using relatively fail-safe means. A cord that complies with the previous section either
as an integral length or in combination with no more than one connectorized
extension cord. If used, the extension cord shall comply with the requirements of 47
CFR Part 68.200(h). Wiring located in an equipment room with restricted access,
provided that this wiring remains exposed for inspection and is not concealed or
embedded in the building’s structure, and that it conforms to 47 CFR Part 68.215(d).
Electrically behind approved (or grandfathered) equipment, system components or
protective circuitry which assure that electrical contact between the wiring and
commercial power wiring or earth ground will not result in hazardous voltages or
excessive longitudinal imbalance at the telephone network interface.

D.2.3.

Protected system premises wiring requiring acceptance testing for imbalance:

Premises wiring which is electrically behind approved (or grandfathered) equipment,
system components or circuitry which assure that electrical contact between the
wiring and commercial power wiring will not result in hazardous voltages at the
telephone network interface.

D.2.4

Unprotected system premises wiring:

All other premises wiring.

160

TIA-968-A

Annex E (informative)

Informative References

E.1.

Part 68 Application Guide: A document produced by TIA TR41.11 Subcommittee on
Administrative Regulatory Considerations to provide administrative guidance on Part
68 implementation.
(See also:

www.tiaonline.org/standards/sfg/tr-41

)

E.2.

Industry Canada, Standard CS-03,

Standard for Terminal Equipment, Systems,

Network Protection Devices and Connection Arrangements.

E.3. ANSI T1.413-1998,

Network and Customer Installation Interfaces – Asymmetric

Digital Subscriber Line (ADSL) Metallic Interface

E.4. ANSI T1.417-2001,

Spectrum Management for Loop Transmission Systems

For additional information about references, contact the respective organizations at the
following addresses:

ANSI

American National Standards Institute
1819 L Street, NW
Washington, DC 20036
(212) 642-4900
www.ansi.org

FCC

Federal Communications Commission
445 12th St. SW
Washington DC 20554
(202) 418-0190
www.fcc.gov

ITU

International Telecommunication Union
Place des Nations
CH-1211 Geneva 20 Switzerland
+41 22 730 51 11
www.itu.int

TIA

Telecommunications Industry Association
2500 Wilson Blvd., Suite 300
Arlington, VA 22201 USA
(703) 907-7700

www.tiaonline.org

161

` TIA-968-A

162

REMOVE THE FOLLOWING BEFORE
PUBLICATION

TR41.9.1 Writing Committee

–

Work Program & Revision Log

(This section is only for the writing groups convenience will be deleted from the final draft.)

Phil Havens, P.E. Chair
John Shinn, P.E. Co-Editor
Anh Nguyen, Co-Editor

Draft
Rev

Date

Description of Change

Authorization

1.0

2.0

3.0

Contribution -005R2 adds transverse balance
requirements- Tim L Cisco
Contribution -017R1 ADSL req'mnts - Peter W Paradyne
Contribution -020 Encoded Analog Content - Trone B
Verizon
Contribution -022 Frequency domain template - Larry Bell
- Adtran
Contribution -060R1 (from Nov 01) Stutter dial tone -
Steve W Vtech
Concept to add Annex to show revision history (see draft
129 for example)

Vancouver
Feb 2002

4.0

1 May 2002

Contribution -006 correct table in 4.5.5.2.1 - Tim L Cisco

Crystal City
May 2002

Document Outline