ISO/FDIS 17987-4
(Main)Road vehicles — Local Interconnect Network (LIN) — Part 4: Electrical physical layer (EPL) specification 12 V/24 V
Road vehicles — Local Interconnect Network (LIN) — Part 4: Electrical physical layer (EPL) specification 12 V/24 V
ISO 17987-4:2016 specifies the 12 V and 24 V electrical physical layers (EPL) of the LIN communications system. The electrical physical layer for LIN is designed for low-cost networks with bit rates up to 20 kbit/s to connect automotive electronic control units (ECUs). The medium that is used is a single wire for each receiver and transmitter with reference to ground. ISO 17987-4:2016 includes the definition of electrical characteristics of the transmission itself and also the documentation of basic functionality for bus driver devices. All parameters in this document are defined for the ambient temperature range from −40 °C to 125 °C.
Véhicules routiers — Réseau Internet local (LIN) — Partie 4: Spécification de la couche électrique physique (EPL) 12V/24V
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International
Standard
ISO/TC 22/SC 31
Road vehicles — Local Interconnect
Secretariat: DIN
Network (LIN) —
Voting begins on:
2025-03-10
Part 4:
Electrical physical layer (EPL)
Voting terminates on:
2025-05-05
specification 12 V/24 V
Véhicules routiers — Réseau Internet local (LIN) —
Partie 4: Spécification de la couche électrique physique (EPL)
12V/24V
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
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TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 22/SC 31
Road vehicles — Local Interconnect
Secretariat: DIN
Network (LIN) —
Voting begins on:
Part 4:
Electrical physical layer (EPL)
Voting terminates on:
specification 12 V/24 V
Véhicules routiers — Réseau Internet local (LIN) —
Partie 4: Spécification de la couche électrique physique (EPL)
12V/24V
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions .1
3.2 Symbols .2
3.3 Abbreviated terms .5
4 Conventions . 6
5 Electrical physical layer requirements . 6
5.1 Bit rate deviation .6
5.1.1 General .6
5.1.2 12 V LIN systems: parameters .6
5.1.3 24 V LIN systems: parameters .7
5.2 Timing requirements .9
5.2.1 Bit timing .9
5.2.2 Synchronization procedure .9
5.2.3 Bit sample timing .10
5.3 Line driver/receiver . 12
5.3.1 General configuration . 12
5.3.2 Definition of supply voltages for the physical interface . 12
5.3.3 Signal specification . 13
5.3.4 12 V LIN systems: electrical parameters .14
5.3.5 24 V LIN systems: Electrical parameters .18
5.3.6 Line characteristics .21
5.3.7 12 V LIN systems: performance in non-operation supply voltage range . 22
5.3.8 24 V LIN systems: performance in non-operation supply voltage range . 22
5.3.9 Performance during fault modes . 22
5.3.10 ESD/EMI compliance . 22
6 Procedures C, D and E . .23
Annex A (informative) LIN peripheral interface design considerations.24
Annex B (normative) LIN AA procedure C physical layer .29
Annex C (normative) LIN AA procedure D physical layer .32
Annex D (normative) LIN AA procedure E physical layer .39
Bibliography .43
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31, Data
communication.
This second edition cancels and replaces the first edition (ISO 17987-4:2016), which has been technically
revised.
The main changes are as follows:
— master and slave terms used for the LIN node types in the ISO 17987 series are replaced within this
document with inclusive language terms commander and responder. This also applies for abbreviations
and file formats NCF and LDF;
— variables and formulae aligned with the ISO/IEC Directives, Part 2;
— updates of several parameter statements and requirements;
— various parameter values adopted in Annex C;
— editorial updates and several statements improved to avoid ambiguities.
A list of all parts in the ISO 17987 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
The LIN protocol as proposed is an automotive focused low speed universal asynchronous receiver
transmitter (UART) based network. Some of the key characteristics of the LIN protocol are signal-based
communication, schedule table-based frame transfer, commander/responder communication with error
detection, node configuration and diagnostic service transportation.
The LIN protocol is for low-cost automotive control applications as, for example, door module and air
conditioning systems. It serves as a communication infrastructure for low-speed control applications in
vehicles by providing:
— signal-based communication to exchange information between applications in different nodes;
— bit rate support from 1 kbit/s to 20 kbit/s;
— deterministic schedule table-based frame communication;
— network management that wakes up and puts the LIN cluster into sleep state in a controlled manner;
— status management that provides error handling and error signalling;
— transport layer that allows large amount of data to be transported (such as diagnostic services);
— specification of how to handle diagnostic services;
— electrical physical layer specifications;
— node description language describing properties of responder nodes;
— network description file describing behaviour of communication;
— application programming interface.
The ISO 17987 series is based on the open systems interconnection (OSI) basic reference model as specified
in ISO/IEC 7498-1 which structures communication systems into seven layers.
The OSI model structures data communication into seven layers called (top down) application layer (layer 7),
presentation layer, session layer, transport layer, network layer, data link layer and physical layer (layer 1). A
subset of these layers is used in the ISO 17987 series.
The ISO 17987 series distinguishes between the services provided by a layer to the layer above it and the
protocol used by the layer to send a message between the peer entities of that layer. The reason for this
distinction is to make the services, especially the application layer services and the transport layer services,
reusable also for o
...
Date: 2024-12
ISO/TC 22/SC 31
Secretariat: DIN
Date: 2025-02-21
Road vehicles — Local Interconnect Network (LIN) —
Part 4:
Electrical Physical Layerphysical layer (EPL) specification 12 V/24
V
Véhicules routiers — Réseau Internet local (LIN) —
Partie 4: Spécification de la couche électrique physique (EPL) 12 V/24 V12V/24V
FDIS stage
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel.Phone: + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
iii
Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols . 2
3.3 Abbreviated terms . 4
4 Conventions . 5
5 Electrical physical layer requirements . 5
5.1 Bit rate deviation . 5
5.2 Timing requirements . 8
5.3 Line driver/receiver . 12
6 Procedures C, D and E . 22
Annex A (informative) LIN peripheral interface design considerations . 23
Annex B (normative) LIN AA procedure C physical layer . 28
Annex C (normative) LIN AA procedure D physical layer . 32
Annex D (normative) LIN AA procedure E physical layer . 40
Bibliography . 44
iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31, Data
communication.
This second edition cancels and replaces the first edition (ISO 17987-14:2016), which has been technically
revised.
The main changes are as follows:
— — master and slave terms used for the LIN node types in the ISO 17987:2016 (all parts) series are
replaced within this standarddocument with inclusive language terms commander and responder. This
also applies for abbreviations and file formats NCF and LDF;
— — variables and formulars adopted toformulae aligned with the ISO directives (part/IEC Directives, Part
2);;
— — updates of several parameter statements and requirements;
— — variables and formulars adopted to the ISO directives (part 2);
— — various parameter values adopted in Annex CAnnex C;;
— — editorial updates and several statements improved to avoid ambiguities.
A list of all parts in the ISO 17987 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
The LIN protocol as proposed is an automotive focused low speed universal asynchronous receiver
transmitter (UART) based network. Some of the key characteristics of the LIN protocol are signal-based
communication, schedule table-based frame transfer, Commandercommander/responder communication
with error detection, node configuration and diagnostic service transportation.
The LIN protocol is for low-cost automotive control applications as, for example, door module and air
conditioning systems. It serves as a communication infrastructure for low-speed control applications in
vehicles by providing:
— — signal-based communication to exchange information between applications in different nodes;
— — bit rate support from 1 kbit/s to 20 kbit/s;
— — deterministic schedule table-based frame communication;
— — network management that wakes up and puts the LIN cluster into sleep state in a controlled manner;
— — status management that provides error handling and error signalling;
— — transport layer that allows large amount of data to be transported (such as diagnostic services);
— — specification of how to handle diagnostic services;
— — electrical physical layer specifications;
— — node description language describing properties of responder nodes;
— — network description file describing behaviour of communication;
— — application programmer’sprogramming interface.
The ISO 17987 series is based on the open systems interconnection (OSI) basic reference model as specified
[11]
in ISO/IEC 7498--1 which structures communication systems into seven layers.
The OSI model structures data communication into seven layers called (top down) application layer (layer 7),
presentation layer, session layer, transport layer, network layer, data link layer and physical layer (layer 1). A
subset of these layers is used in Thethe ISO 17987 series.
The ISO 17987 series distinguishes between the services provided by a layer to the layer above it and the
protocol used by the layer to send a message between the peer entities of that layer. The reason for this
distinction is to make the services, especially the application layer services and the transport layer services,
reusable also for other types of networks than LIN. In this way, the protocol is hidden from the service user
and it is possible to change the protocol if special system requirements demand it.
The ISO 17987 series provides all documents and references required to support the implementation of the
requirements related to the following.
— — ISO 17987--1: provides an overview of the ISO 17987 series and structure along with the use case
definitions and a common set of resources (definitions, references) for use by all subsequent parts.
— — ISO 17987--2: specifies the requirements related to the transport protocol and the network layer
requirements to transport the PDU of a message between LIN nodes.
vi
— — ISO 17987--3: specifies the requirements for implementations of the LIN protocol on the logical level
of abstraction. Hardware-related properties are hidden in the defined constraints.
— — ISO 17987--4 (this document): specifies the requirements for implementations of active hardware
components which are necessary to interconnect the protocol implementation.
— — ISO/TR 17987--5: specifies the LIN application programmersprogramming interface (API) and the
node configuration and identification services. The node configuration and identification services are
specified in the API and define how a responder node is configured and how a responder node uses the
identification service.
— — ISO 17987--6: specifies tests to check the conformance of the LIN protocol implementation according
to ISO 17987--2 and ISO 17987--3. This comprises tests for the data link layer, the network layer and the
transport layer.
— — ISO 17987--7: specifies tests to check the conformance of the LIN electrical physical layer
implementation (logical level of abstraction) according to this document.
vii
DRAFT International Standard ISO/FDIS 21068-2:—(en)
Road vehicles — Local Interconnect Network (LIN) — Part 4: Electrical
physical layer (EPL) specification 12 V/24 V
Part 4:
Electrical physical layer (EPL) specification 12 V/24 V
1 Scope
This document specifies the 12 V and 24 V electrical physical layers (EPL) of the LIN communications system.
The electrical physical layer for LIN is designed for low-cost networks with bit rates up to 20 kbit/s to connect
automotive electronic control units (ECUs). The medium that is used is a single wire for each receiver and
transmitter with reference to ground.
Annex AAnnex A provides recommendations on the LIN physical layer peripheral interface design of type
UART and frame controller for commander and responder nodes.
This document includes the definition of electrical characteristics of the transmission itself and also the
documentation of basic functionality for bus driver devices.
NodesThis document also provides the physical layer definitions for nodes with LIN AA capabilities according
to one of the procedures C, D and E shall conform to the appropriate physical layer definitions according to
Annex B, Annex C or Annex D.
All parameters in this document are defined for the ambient temperature range from −40 °C to 125 °C.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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.
ISO 17987-1, Road vehicles — Local Interconnect Network (LIN) — Part 1: General information and use case
definition
IEC 61000--4--2, Electromagnetic compatibility (EMC) — Part 4-2: Testing and measurement techniques —
Electrostatic discharge immunity test
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions given in ISO 17987-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1.1 3.1.1
BR_Range_20K
LIN systems which operate at speeds up to 20 kbit/s
3.1.2 3.1.2
BR_Range_20K 12 V
12 V LIN systems which operate at speeds up to 20 kbit/s
3.1.3 3.1.3
BR_Range_20K 24 V
24 V LIN systems which operate at speeds up to 20 kbit/s
3.1.4 3.1.4
BR_Range_10K
LIN systems which operate at speeds up to 10,417 kbit/s
3.1.5 3.1.5
BR_Range_10K
...
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