ETSI TBR 024 ed.1 (1997-07)

SLOVENSKI STANDARD
SIST TBR 024 E1:2004
01-oktober-2004

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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 .......................................................................11

4.2.1.4 Output jitter ..........................................................................11

4.2.1.5 Output frame structure.........................................................12

4.2.2 Input port .......................................................................................................12

4.3 Safety.................................................................................................................................13

4.4 Overvoltage protection.......................................................................................................13

4.5 ElectroMagnetic Compatibility (EMC) ................................................................................13

Annex A (normative): Test methods......................................................................................................14

A.1 General..............................................................................................................................................14

A.1.1 Equipment connection .......................................................................................................14

A.1.2 Test environment ...............................................................................................................14

A.2 Test methods ....................................................................................................................................15

A.2.1 Signal coding at the output port .........................................................................................15

A.2.2 Waveform shape at the output port ...................................................................................15

A.2.3 Output timing......................................................................................................................16

A.2.4 Output jitter ........................................................................................................................17

A.2.5 Frame structure .................................................................................................................18

Annex B (normative): Definition of HDB3 code .....................................................................................19

B.1 General..............................................................................................................................................19

B.2 Definition ...........................................................................................................................................19

Annex C (normative): Definition of frame structure ...............................................................................20

C.1 Frame structure at 34 368 kbit/s .......................................................................................................20

Annex D (normative): TBR Requirements Table (TBR-RT)..................................................................21

Annex E (informative): Bibliography........................................................................................................22

History..........................................................................................................................................................23

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 34 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 Recommendation 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 34 368 kbit/s digital unstructured leased

- connection to the NTPs of 34 368 kbit/s digital structured leased lines (D34S) 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 D34U or D34S 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 D34U leased lines which do not comply with the

specified requirements on output structure, do not satisfy the attachment requirements for connection to

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 D34U 34 368 kbit/s unstructured leased line provides a bi-directional point-to-point digital connection

with an information transfer rate of 34 368 kbit/s without restriction on binary content. Any structuring of

The D34S 34 368 kbit/s structured leased line provides a bi-directional point-to-point digital connection

with an information transfer rate of 33 920 kbit/s without restriction on binary content. Any structuring of

the data within the transparent 33 920 kbit/s part of the frame is the responsibility of the user.

For both D34U and D34S 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 High Density Bipolar code 3

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 figure 2 and

Pulse shape (nominally rectangular) All marks of a valid signal shall conform with the

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 34 368 kbit/s ± 20 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