Safety aspects for xDSL signals on circuits connected to telecommunication networks (DSL: Digital Subscriber Line)

This technical specification addresses the safety implications of having xDSL signals on circuits in equipment connected to a TELECOMMUNICATION NETWORK, and gives rules for dealing with such equipment in the context of the IEC 60950 series

General Information

Status
Published
Publication Date
26-Jan-2004
Current Stage
PPUB - Publication issued
Start Date
27-Jan-2004
Completion Date
27-Jan-2004
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IEC TS 62367:2004 - Safety aspects for xDSL signals on circuits connected to telecommunication networks (DSL: Digital Subscriber Line)
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TECHNICAL IEC
SPECIFICATION
TS 62367
First edition
Pre-Standard
2004-01
Safety aspects for xDSL signals on circuits
connected to telecommunication networks
(DSL: Digital Subscriber Line)
Reference number
IEC/TS 62367:2004(E)
---------------------- Page: 1 ----------------------
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.
Consolidated editions

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---------------------- Page: 2 ----------------------
TECHNICAL IEC
SPECIFICATION
TS 62367
First edition
Pre-Standard
2004-01
Safety aspects for xDSL signals on circuits
connected to telecommunication networks
(DSL: Digital Subscriber Line)
 IEC 2004  Copyright - all rights reserved

No part of this publication may be reproduced or utilized in any form or by any means, electronic or

mechanical, including photocopying and microfilm, without permission in writing from the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

PRICE CODE
Commission Electrotechnique Internationale M
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
---------------------- Page: 3 ----------------------
– 2 – TS 62367  IEC:2004(E)
CONTENTS

FOREWORD...........................................................................................................................3

INTRODUCTION.....................................................................................................................5

1 Scope...............................................................................................................................6

2 Normative references .......................................................................................................6

3 Terms, definitions and abbreviations ................................................................................6

4 xDSL signals on circuits connected to telecommunication networks..................................7

Annex A (informative) xDSL telecommunication systems .......................................................8

A.1 Introduction ......................................................................................................................8

A.2 General description ..........................................................................................................8

A.3 Peak-to average ratio and CF...........................................................................................9

A.4 CF distribution................................................................................................................10

A.5 Line termination impedance............................................................................................12

A.6 Measurement of xDSL parameters..................................................................................12

Bibliography..........................................................................................................................13

Figure A.1 – Typical configuration of an xDSL system.............................................................8

Figure A.2 – Typical xDSL (VDSL) signal in the time-domain ..................................................9

Figure A.3 – Probability of symbol with CF >x .......................................................................11

Figure A.4 – Inter-arrival time of symbol with CF > x (DMT-symbol rate = 4 kHz) ..................11

---------------------- Page: 4 ----------------------
TS 62367  IEC:2004(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY ASPECTS FOR XDSL SIGNALS ON CIRCUITS
CONNECTED TO TELECOMMUNICATION NETWORKS
(DSL: DIGITAL SUBSCRIBER LINE)
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

The main task of IEC technical committees is to prepare International Standards. In

exceptional circumstances, a technical committee may propose the publication of a technical

specification when

• the required support cannot be obtained for the publication of an International Standard,

despite repeated efforts, or

• the subject is still under technical development, or where, for any other reason, there is

the future but no immediate possibility of an agreement on an International Standard.

Technical specifications are subject to review within three years of publication to decide

whether they can be transformed into International Standards.

IEC-TS 62367, which is a technical specification, has been prepared by IEC technical

committee 108: Safety of electronic equipment within the field of audio/video, information

technology and communication technology.

This technical specification is a pre-standard publication which may be updated in the future

as an International Standard.
---------------------- Page: 5 ----------------------
– 4 – TS 62367  IEC:2004(E)
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
108/61/DTS 108/90/RVC

Full information on the voting for the approval of this technical specification can be found in

the report on voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

In this standard, terms defined in 1.2 of IEC 60950-1are printed in SMALL CAPITALS.

The committee has decided that the contents of this publication will remain unchanged until

2007. At this date, the publication will be
• transformed into an International Standard;
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
---------------------- Page: 6 ----------------------
TS 62367  IEC:2004(E) – 5 –
INTRODUCTION
xDSL signals are high-speed telecommunication signals that may be present on a
telecommunication line, together with:
– analogue PSTN (Public Switched Telephone Network);
– ISDN (Integrated Services Digital Network) signals; or
– a d.c. power-feeding component.

An xDSL signal is characterised by an amplitude of the order of 3 V r.m.s. with superimposed

spikes having very short duration (about 1 μs) and peak values not exceeding 30 V.

When combined with other services as above, the peak voltage can very occasionally exceed

the limits for a TNV-3 CIRCUIT. However the excursions above these limits consist of these very

short duration spikes.

There are no published documents from IEC on the effect of such spikes on the human body,

but experience with xDSL is that the safety risk, if any, is very small because of:

– the low power of the spikes; and
– the limited accessibility of TNV circuits.
The amplitude and probability of the spikes have been calculated as follows:

– amplitude up to 15V/1μs with a probability of occurrence of one every few seconds to

every few minutes;

– amplitude up to 20V/1μs with a probability of occurrence of one every few hours;

– amplitude up to 27V/1μs with a probability of occurrence of one every few years.

Annex A gives more detail on the operation of xDSL telecommunication systems.
---------------------- Page: 7 ----------------------
– 6 – TS 62367  IEC:2004(E)
SAFETY ASPECTS FOR XDSL SIGNALS ON CIRCUITS
CONNECTED TO TELECOMMUNICATION NETWORKS
(DSL: DIGITAL SUBSCRIBER LINE)
1 Scope

This technical specification addresses the safety implications of having xDSL signals on

circuits in equipment connected to a TELECOMMUNICATION NETWORK, and gives rules for dealing

with such equipment in the context of the IEC 60950 series.
2 Normative references

The following referenced documents are indispensable for the application of this document.

For dated references, only the edition cited applies. For undated references, the latest edition

of the referenced document (including any amendments) applies.
IEC 60950 (all parts), Information technology equipment – Safety

IEC 60950-1 (all parts), Information technology equipment – Safety – Part 1: General

requirem
...

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