ETSI TBR 025 ed.1 (1997-07)

SLOVENSKI STANDARD
SIST TBR 025 E1:2004
01-oktober-2004
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Business TeleCommunications (BTC); 140 Mbit/s digital unstructured and structured

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Key words: Access, digital, interface, leased line, ONP, terminal, testing, type approval

Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the

Whilst every care has been taken in the preparation and publication of this document, errors in content,

typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to

"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Foreword........................................................................................................................................................5

Introduction....................................................................................................................................................5

1 Scope ..................................................................................................................................................7

2 Normative references..........................................................................................................................7

3 Definitions and abbreviations ..............................................................................................................7

3.1 Definitions ............................................................................................................................7

3.2 Abbreviations .......................................................................................................................8

4 Requirements......................................................................................................................................9

4.1 Mechanical characteristics...................................................................................................9

4.2 Electrical characteristics ....................................................................................................10

4.2.1 Output port ....................................................................................................10

4.2.1.1 Signal coding .......................................................................10

4.2.1.2 Waveform shape .................................................................10

4.2.1.3 Output timing .......................................................................12

4.2.1.4 Output jitter ..........................................................................13

4.2.1.5 Output frame structure.........................................................14

4.2.2 Input port .......................................................................................................14

4.3 Safety.................................................................................................................................15

4.4 Overvoltage protection.......................................................................................................15

4.5 ElectroMagnetic Compatibility (EMC) ................................................................................15

Annex A (normative): Test methods......................................................................................................16

A.1 General..............................................................................................................................................16

A.1.1 Equipment connection .......................................................................................................16

A.1.2 Test environment ...............................................................................................................16

A.2 Test methods ....................................................................................................................................17

A.2.1 Signal coding at the output port .........................................................................................17

A.2.2 Waveform shape at the output port ...................................................................................17

A.2.3 Output timing......................................................................................................................18

A.2.4 Output jitter ........................................................................................................................19

A.2.5 Frame structure .................................................................................................................20

Annex B (normative): Definition of CMI code ........................................................................................21

B.1 General..............................................................................................................................................21

B.2 Definition ...........................................................................................................................................21

Annex C (normative): Definition of frame structure ...............................................................................22

C.1 Frame structure at 139 264 kbit/s .....................................................................................................22

Annex D (normative): TBR Requirements Table (TBR-RT) ..................................................................23

Annex E (informative): Bibliography........................................................................................................24

History..........................................................................................................................................................25

This Technical Basis for Regulation (TBR) has been produced by the Business TeleCommunications

(BTC) Technical Committee, in conjunction with the Terminal Equipment (TE) and Transmission and

Multiplexing (TM) Technical Committees, of the European Telecommunications Standards Institute

This TBR resulted from a mandate from the Commission of the European Community (CEC) to provide

This TBR is based on information from ITU-T Recommendations and ETSI publications and the relevant

The Council Directive on the application of Open Network Provision (ONP) to leased lines (92/44/EEC)

concerns the harmonization of conditions for open and efficient access to, and use of, the leased lines

provided over public telecommunications networks, and the availability throughout the European Union of

At the date of publication of this TBR, the 140 Mbit/s unstructured and structured leased lines are not part

of the minimum set of leased lines under the Leased Line Directive and it is not planned that they will be

Two classes of standard will be used for the interfaces of terminal equipment designed for connection to

the ONP leased lines. European Telecommunications Standards (ETSs), which are voluntary, give the full

technical specifications for these interfaces, whereas TBRs give the essential requirements under the

Second Phase Directive (91/263/EEC) for attachment to the leased lines. This TBR is a subset of the

ETS 300 166 and ITU-T Recommendations G.703 are used as the basis for the terminal equipment

This TBR specifies the attachment requirements and the corresponding conformance tests for a terminal

- connection to the Network Termination Points (NTPs) of 139 264 kbit/s digital unstructured leased

- connection to the NTPs of 139 264 kbit/s digital structured leased lines (D140S) with an information

The term "attachment requirements" in the context of this TBR refers to the essential requirements for

access that apply under articles 4d and 4f of the Second Phase Directive (91/263/EEC). Conformance to

these requirements does not guarantee end-to-end interoperability. Essential requirements under articles

This TBR is applicable to all interfaces intended for connection to the D140U or D140S leased line. It

covers the essential requirements for the mechanical and electrical characteristics of the terminal

equipment interface. Interfaces intended only for connection to the D140U leased lines which do not

comply with the specified requirements on output structure, do not satisfy the attachment requirements for

Customer premises wiring and installation between the terminal equipment and the NTP are outside the

This TBR incorporates by dated or undated reference, provisions from other publications. These

normative references are cited at the appropriate places in the text and the publications are listed

hereafter. For dated references, subsequent amendments to, or revisions of any of these publications

apply to this TBR only when incorporated into it by amendment or revision. For undated references the

NOTE: This TBR also contains a number of informative references which have been included

to indicate the sources from which various material has been derived, hence they do

not have an associated normative reference number. Details of these publications are

frame: A repetitive set of consecutive bits in which the position of each bit can be identified by reference

frame alignment signal: The distinctive signal inserted in every frame always occupying the same

relative position within the frame and used to establish and maintain frame alignment.

leased lines: The telecommunications facilities provided by a public telecommunications network that

provide defined transmission characteristics between network termination points and that do not include

Network Termination Point (NTP): All physical connections and their technical access specifications

which form part of the public telecommunications network and are necessary for access to and efficient

PRBS(2 ): A Pseudo Random Bit Sequence (PRBS) (as defined in subclause 2.2 of ITU-T

Safety Extra-Low Voltage (SELV) circuit: A secondary circuit which is so designed and protected that

under normal and single fault conditions, the voltage between any two accessible parts and, for class 1

equipment, between any accessible part and the equipment protective earthing terminal does not exceed

terminal equipment: Equipment intended to be connected to the public telecommunications network, i.e.:

- to be connected directly to the termination of a public telecommunication network; or

- to interwork with a public telecommunications network being connected directly or indirectly to the

TX TX is a signal output (at either the terminal equipment or the test equipment,

The D140U 139 264 kbit/s unstructured leased line provides a bi-directional point-to-point digital

connection with an information transfer rate of 139 264 kbit/s without restriction on binary content. Any

The D140S 139 264 kbit/s structured leased line provides a bi-directional point-to-point digital connection

with an information transfer rate of 138 240 kbit/s without restriction on binary content. Any structuring of

the data within the transparent 138 240 kbit/s part of the frame is the responsibility of the user.

For both D140U and D140S the provision of timing is the responsibility of the user; however, in certain

installations the leased line provider may be able to offer a leased line that is synchronized to the network.

Justification: Without a means of connection, it is impossible for the terminal equipment to connect to the

network, therefore this is included in order for the terminal equipment to interwork with the network

Requirement: The terminal equipment interface shall provide two coaxial 75 Ω connectors, one each for

There is no requirement under this TBR for a particular plug or socket to be provided on the terminal

NOTE 2: The transmit pair is the output from the terminal equipment interface. The receive pair

is the input to the terminal equipment interface, as shown in figure 1. Where the terms

"output" and "input" are used without qualification in this TBR, they refer to the terminal

NOTE 3: Normal practice is for the outer conductors of the input and output connectors to be

connected via a dc path to the signal ground and thence to ground. This connection is

to reduce EMC emissions. If there is a difference in ground potential between the

terminal equipment and the NTP, this arrangement may result in high currents in the

conductor and the signal ground in the terminal equipment. Careful attention should be

Justification: The correct signal coding is necessary for the output signals from the terminal equipment to

be recognized correctly at the input to the NTP. Failure to provide the correct coding may cause error

reports within the network. A requirement on signal coding is therefore included in order to prevent harm

Requirement: The signal transmitted at the output port shall comply with the Coded Mark Inversion (CMI)

Justification: The correct waveform shape both limits the voltages to line and ensures correct recognition

of the pulses. Incorrect recognition of pulses may cause error reports within the network. A requirement on

waveform shape is therefore included in order to prevent harm to the network (article 4d).

Requirement: The pulse at the output port shall comply with the requirements given in figures 2 and 3

NOTE 1: The maximum "steady state" amplitude shall not exceed the 0,55 V limit. Overshoots and other

transients are permitted to fall into the dotted area, bounded by the amplitude levels 0,55 V and

NOTE 2: The rise time and decay time shall be measured between -0,4 V and 0,4 V and shall not

NOTE 1: The maximum "steady state" amplitude shall not exceed the 0,55 V limit. Overshoots and other

transients are permitted to fall into the dotted area, bounded by the amplitude levels 0,55 V and

NOTE 2: The inverse pulse shall have the same characteristics, noting that the timing tolerance at the

level of the negative and positive transitions are ± 0,1 ns and ± 0,5 ns respectively.

NOTE 3: The rise time and decay time shall be measured between -0,4 V and 0,4 V and shall not

the mean value of the 50 %amplitude Positive transitions at unit interval boundaries: ± 0,5 ns

points of the negative transition) Positive transitions at mid-interval: ± 0,35 ns

Justification: Pulses at the wrong bit rate may not be properly recognized and may cause error reports

within the network. A requirement on output timing is therefore included in order to prevent harm to the

Requirement: For each of the timing arrangements intended for use, the bit rate at the output port shall

be within the limits of 139 264 kbit/s ± 15 parts per million (ppm), when any relevant external reference

signal, including the received signal at the input port, is within its stated tolerance.

Justification: A high level of jitter causes error reports within some networks, therefore this requirement

Requirement: The peak-to-peak output jitter shall not exceed the limits of table 2 when measured with a

band pass filter with the defined cut-off frequencies. At frequencies below the lower 3 dB point, the

attenuation of the high pass filter shall rise with a value greater than, or equal to, 20 dB per decade. At

frequencies above the upper 3 dB point, the attenuation of the low pass filtration shall rise with a value

For the purpose of testing, any signal input from which the output timing is derived shall be provided with

the maximum tolerable input jitter, and with the maximum tolerable input frequency deviation, as specified

Where the output timing of the terminal equipment is taken from the leased line, the input to the terminal

equipment shall be provided with components of sinusoidal jitter at points on the curve of figure 4 and

Justification: If the input bit stream to the structured leased line does not have the correct Frame

Alignment bytes 1 (FA1) and Frame Alignment bytes 2 (FA2), the leased line will not be able to achieve

frame alignment for the purposes of monitoring the line and may cause error reports. Therefore a

requirement on the frame alignment signals is included to prevent harm to the network (article 4d).

Requirement: For terminal equipments intended for connection to the D140S structured leased line,

the bit stream transmitted at the output of the terminal equipment shall be structured as defined in

There are no requirements on the input port under this TBR, except as specified in subclause 4.1.

Justification: The requirements imposed on the terminal equipment output port do not require the correct

receipt of data at the terminal equipment input port. The network output port should be protected against

both short circuit and open circuit. Therefore there are no requirements within the base standard

NOTE: Safety requirements are imposed under the Low Voltage Directive (73/23/EEC) and

Voltage (SELV) circuit. Detailed requirements for SELV circuits are given in EN 60950.

NOTE: Requirements for overvoltage protection requirements on a 75 Ω interface are under

specifications become available if these requirements are not imposed under the EMC

This annex describes the test principles to determine the compliance of a terminal equipment against the

It is outside the scope of this TBR to identify the specific details of the implementation of the tests.

A terminal equipment may be designed for through-connecting and may fulfil the electrical requirements

only if through-connected. In these cases the requirements of this TBR are valid and the tests are carried

out with the through-connection terminated as specified by the equipment supplier.

Details of test equipment accuracy and the specification tolerance of the test devices are not included in

all cases. Where such details are provided they shall be complied with, but the way they are expressed

NOTE: Attention is drawn to the issue of measurement uncertainty which may be addressed in

future documents. Not all the required test results make allowance for spurious events

during testing (e.g. errors due to EMC effects), which may make it necessary to repeat

The given test configurations do not imply a specific realization of the test equipment or test arrangement,

or the use of specific test devices. However any test configuration used shall provide those test conditions

specified under "interface state", "stimulus" and "monitor" for each individual test.

The test equipment shall be a device, or a group of devices, generating a stimulus signal conforming to

The terminal equipment interface under test shall have the ability to transmit a bit pattern for test

purposes, e.g. a Pseudo Random Bit Sequence (PRBS(2 )) as defined in subclause 2.2 of ITU-T

Recommendation O.151 [2]. Where this cannot be provided, an alternative method of conducting the test

The tests shall be applied at the sockets or plugs supplied with the terminal equipment for connection to

the leased line interface. Connecting cable between the sockets and test equipment shall be kept to a

Where plugs are provided at the end of a cord, the tests specified in subclause A.2.2 may be performed at

the point of connection of the cord to the terminal equipment, since the requirements are based on ITU-T

For terminal equipment which is not designed to operate within the environmental range specified above,

all tests shall be performed in an environmental condition as specified by the supplier.

For terminal equipment which is directly powered (either wholly or partly) from the mains supply, all tests

shall be carried out with ± 5 % of the rated voltage of that supply. If the equipment is powered by other