IEC 62056-42:2002

INTERNATIONAL IEC
STANDARD
62056-42
First edition
2002-02
Electricity metering –
Data exchange for meter reading,
tariff and load control –
Part 42:
Physical layer services and procedures
for connection-oriented asynchronous
data exchange
Reference number
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INTERNATIONAL IEC
STANDARD
62056-42
First edition
2002-02
Electricity metering –
Data exchange for meter reading,
tariff and load control –
Part 42:
Physical layer services and procedures
for connection-oriented asynchronous
data exchange
 IEC 2002  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 Geneva, Switzerland
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International Electrotechnical Commission
For price, see current catalogue

– 2 – 62056-42  IEC:2002(E)
CONTENTS
FOREWORD .4
1 Scope.5
2 Normative references .5
3 Terms, definitions and abbreviations .6
4 Overview .7
5 Service specification.8
5.1 List of services .8
5.1.1 Connection establishment/release related services.8
5.1.2 Data communication services .8
5.1.3 Layer management services .8
5.2 Use of the physical layer services .9
5.3 Service definitions .9
5.3.1 PH-CONNECT.request .9
5.3.2 PH-CONNECT.indication .10
5.3.3 PH-CONNECT.confirm .10
5.3.4 PH-ABORT.request .11
5.3.5 PH-ABORT.confirm .11
5.3.6 PH-ABORT.indication .11
5.3.7 PH-DATA.request .12
5.3.8 PH-DATA.indication.12
6 Protocol specification .13
6.1 Physical layer protocol data unit.13
6.2 Transmission order and characteristics .13
6.3 Physical layer operation – description of the procedures .13
6.3.1 General .13
6.3.2 Setting up a physical connection .14
6.3.3 The identification service .15
6.3.4 Data communications .19
6.3.5 Disconnection of an existing physical connection.19
Annex A (informative) An example: PH service primitives and Hayes commands .20
Annex B (informative) Data model and protocol .25
Bibliography.26
Figure 1 – Typical PSTN configuration .7
Figure 2 – The location of the physical layer .8
Figure 3 – Protocol layer services of the COSEM 3-layer connection oriented profile.9
Figure 4 – MSC for physical connection establishment.15
Figure 5 – MSC for IDENTIFY.request/.response message exchange .17
Figure 6 – Handling the identification service at the COSEM server side.17
Figure 7 – Partial state machine for the client side physical layer.18
Figure A.1 – MSC for physical connection request .20
Figure A.2 – Physical connection establishment at the CALLING station.21
Figure A.3 – MSC for physical connection establishment .22
Figure A.4 – Data exchange between the calling and called stations.23
Figure A.5 – MSC for a physical disconnection .24
Figure B.1 – The three-step approach of COSEM .25

62056-42  IEC:2002(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
ELECTRICITY METERING – DATA EXCHANGE
FOR METER READING, TARIFF AND LOAD CONTROL –
Part 42: Physical layer services and procedures for
connection-oriented asynchronous data exchange
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
The International Electrotechnical Commission (IEC) draws attention to the fact that it is claimed that compliance
with this International Standard may involve the use of a maintenance service concerning the stack of protocols on
which the present standard IEC 62056-42 is based.
The IEC takes no position concerning the evidence, validity and scope of this maintenance service.
The provider of the maintenance service has assured the IEC that he is willing to provide services under
reasonable and non-discriminatory terms and conditions for applicants throughout the world. In this respect, the
statement of the provider of the maintenance service is registered with the IEC. Information (see also 6.3.3) may
be obtained from:
DLMS User Association
Geneva / Switzerland
www.dlms.ch
International Standard IEC 62056-42 has been prepared by IEC technical committee 13:
Equipment for electrical energy measurement and load control.
The text of this standard is based on the following documents:
FDIS Report on voting
13/1266/FDIS 13/1272/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
_________
Device Language Message Specification.

– 4 – 62056-42  IEC:2002(E)
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annexes A and B are for information only.
The committee has decided that the contents of this publication will remain unchanged until
2006. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

62056-42  IEC:2002(E) – 5 –
ELECTRICITY METERING – DATA EXCHANGE
FOR METER READING, TARIFF AND LOAD CONTROL –
Part 42: Physical layer services and procedures for
connection-oriented asynchronous data exchange
1 Scope
This part of IEC 62056 specifies the physical layer services and protocols within the
Companion Specification for Energy Metering (COSEM) three-layer connection oriented
profile for asynchronous data communication. The document does not specify physical layer
signals and mechanical aspects. Local, implementation-specific issues are also not specified.
In annex A, an example of how this physical layer can be used for data exchange through the
Public Switched Telephone Network (PSTN) using intelligent Hayes modems is given.
The use of the physical layer for the purposes of direct local data exchange using an optical
port or a current loop physical interface is specified in IEC 62056-21.
Annex B gives an explanation of the role of data models and protocols in electricity meter
data exchange.
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 60050-300:2001, International Electrotechnical Vocabulary –Electrical and electronic
measurements and measuring instruments – Part 311: General terms relating to
measurements – Part 312: General terms relating to electrical measurements – Part 313:
Types of electrical measuring instruments – Part 314: Specific terms according to the type of
instrument
IEC/TR 62051:1999, Electricity metering – Glossary of terms
IEC 62056-21, Electricity metering – Data exchange for meter reading, tariff and load control –
Part 21: Direct local data exchange
IEC 62056-46, Electricity metering – Data exchange for meter reading, tariff and load control –
Part 46: Data link layer using HDLC protocol
IEC 62056-53, Electricity metering – Data exchange for meter reading, tariff and load control –
Part 53: COSEM application layer
IEC 62056-61, Electricity metering – Data exchange for meter reading, tariff and load control
– Part 61: OBIS Object identification system
IEC 62056-62, Electricity metering – Data exchange for meter reading, tariff and load control –
Part 62: Interface objects
NEMA C12.21:1999, Protocol Specification for Telephone Modem Communication
_________
To be published.
– 6 – 62056-42  IEC:2002(E)
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purpose of this part of IEC 62056, the definitions in IEC 60050-300 and IEC/TR 62051
as well as
...