IEC 60839-7-3:2001

INTERNATIONAL IEC
STANDARD
60839-7-3
First edition
2001-03
Alarm systems –
Part 7-3:
Message formats and protocols for serial data
interfaces in alarm transmission systems –
Common data link layer protocol
Systèmes d'alarme –
Partie 7-3:
Formats de message et protocoles pour les interfaces de
données série dans les systèmes de transmission d'alarme –
Protocole de la couche commune de liaison de données

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INTERNATIONAL IEC
STANDARD
60839-7-3
First edition
2001-03
Alarm systems –
Part 7-3:
Message formats and protocols for serial data
interfaces in alarm transmission systems –
Common data link layer protocol
Systèmes d'alarme –
Partie 7-3:
Formats de message et protocoles pour les interfaces de
données série dans les systèmes de transmission d'alarme –
Protocole de la couche commune de liaison de données

 IEC 2001  Copyright - all rights reserved
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International Electrotechnical Commission
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– 2 – 60839-7-3 © IEC:2001(E)
CONTENTS
Page
FOREWORD . 3

Clause
1 Scope . 5

2 Normative references . 5

3 Definitions. 5
4 Abbreviations . 5
5 General. 6
6 Data link data block. 6
7 Basic transmission protocol. 7
7.1 Message time-out. 7
7.2 Restart time-out . 7
7.3 Network addresses . 7
7.4 MASTER initialization. 7
7.5 SLAVE initialization . 8
7.6 Data link layer authentication (DLLA) function. 8
7.7 Normal state . 9
7.8 Multipoint operation. 9
7.9 Wait state . 10
7.10 Message From MASTER . 10
7.11 SLAVE to SLAVE communications . 10
7.12 General protocol . 11
7.12.1 Reception errors. 11
7.12.2 Response. 11
7.12.3 Failure to respond . 11
7.12.4 Re-initialization of SLAVEs . 11
7.12.5 Failure of the MASTER. 11
Annex A (normative)  Data link data block types. 12

60839-7-3 © IEC:2001(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

––––––––
ALARM SYSTEMS –
Part 7-3: Message formats and protocols for serial data interfaces

in alarm transmission systems –

Common data link layer protocol

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.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60839-7-3 has been prepared by IEC technical committee 79: Alarm
systems.
The text of this standard is based on the following documents:
FDIS Report on voting
79/200/FDIS 79/210/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annex A forms an integral part of this standard.
The committee has decided that the contents of this publication will remain unchanged until
2004. At this date, the publication will be
reconfirmed;
withdrawn;
replaced by a revised edition, or
amended.
– 4 – 60839-7-3 © IEC:2001(E)
A bilingual version of this standard may be issued at a later date.

IEC 60839-7-3 forms one of a number of related parts presented under the general title: Alarm

systems – Part 7: Message formats and protocols for serial data interfaces in alarm

transmission systems:
IEC 60839-7-1: General
IEC 60839-7-2: Common application layer protocol

IEC 60839-7-3: Common data link layer protocol

IEC 60839-7-4: Common transport layer protocol

IEC 60839-7-5: Alarm system interfaces employing a two-wire configuration in accordance
with ISO/IEC 8482
IEC 60839-7-6: Alarm system interfaces employing ITU-T Recommendation V.24/V.28
signals
IEC 60839-7-7: Alarm system interfaces for plug-in alarm system transceivers
IEC 60839-7-11: Serial protocol for use by digital communicator systems using ITU-T
Recommendation V.23 signalling at interfaces with the PSTN
IEC 60839-7-12: PTT interfaces for dedicated communications using ITU-T
Recommendation V.23 signalling
IEC 60839-7-20: Terminal interfaces employing ITU-T Recommendation V.24/V.28
signalling
60839-7-3 © IEC:2001(E) – 5 –
ALARM SYSTEMS –
Part 7-3: Message formats and protocols for serial data interfaces

in alarm transmission systems –

Common data link layer protocol

1 Scope
This part of IEC 60839 specifies the data link layer message structure, formats and
transmission procedures which should be used at standard serial data interfaces in alarm
transmission systems where the transmission network employed does not offer a standard
protocol. This is necessary in order to ensure compatibility of equipment from different
suppliers.
The standard applies equally to the transmission of alarms and other messages to/from
intrusion, fire, access control and social alarm systems, and to the transmission of information
to/from other similar systems.
The protocol is based on a simple poll response algorithm, with a single MASTER and one or
more SLAVEs. The protocol defined allows for point-point and point-multipoint operation.
Multipoint to multipoint operation is not supported, however the structure does support the
transmission of messages from one SLAVE to another, using the MASTER as a simple router.
The structure follows the OSI recommendations for a layered protocol to allow flexibility in the
use of the physical layer.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60839. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 60839 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60839-5-1, Alarm systems – Part 5: Requirements for alarm transmission systems –

Section 1: General requirements for systems
IEC 60839-7-1, Alarm systems – Part 7-1: Message formats and protocols for serial data inter-
faces in alarm transmission systems – General
3 Definitions
For the purpose of this part of IEC 60839, the definitions in IEC 60839-7-1 apply.
4 Abbreviations
The abbreviations in IEC 60839-7-1 apply.

– 6 – 60839-7-3 © IEC:2001(E)
5 General
The basic protocol employed is a poll-response, with a single MASTER. Where there is more

than a single SLAVE, the MASTER will normally poll each slave in turn.

Messages requiring transmission shall be formatted into one or more data link data blocks,

which shall be transmitted in order to the intended destination.

Each transmitted data link data block shall be explicitly acknowledged before the transmission

of a subsequent block.
6 Data link data block
The data link shall transmit messages with the following structure:
STX
LENGTH
SLAVE ADDRESS
KS R
(5 bits)
X/Y
DATA LINK DATA BLOCK TYPE
DATA LINK DATA
max. 248 octets
CRC
The STX octet shall be 02 HEX.
The message LENGTH shall be the number of octets following the LENGTH octet up to (and
including) the CRC.
The bit K (bit 7 of 3rd octet) shall be set (=1) to specify a message in which the data link layer
authentication (DLLA) function is active, and unset (=0) where it is not.

The bit R (bit 5 of 3rd octet) is reserved and should be unset (=0).
The bit S (bit 6 of 3rd octet) is a sequence bit, and shall initially be unset (=0). The bit shall be
set (=1) in the INIT DLLA data link data block type and shall be toggled for each new message
transmitted by the MASTER. A SLAVE shall always set the S bit equal to the corresponding bit
in the incoming message.
The X/Y octet is set to X for messages transmitted from the MASTER, and to Y for messages
transmitted from a SLAVE.
T
...