Road vehicles — Interchange of digital information on electrical connections between towing and towed vehicles — Part 2: Application layer for brakes and running gear

ISO 11992-2:2014 specifies the parameters and messages for electronically controlled braking systems, including anti-lock braking systems (ABS) and vehicle dynamics control systems (VDC), as well as for running gear equipment (i.e. systems for steering, suspension, and tyres), to ensure that the data communication interchange of information between road vehicles with a maximum authorized total mass greater than 3 500 kg and their towed vehicles, including the communication between (several) towed vehicles, on a dedicated network. It does not include any other communication on that network that is not related to the communication between those vehicles.

Véhicules routiers — Échange d'informations numériques sur les connexions électriques entre véhicules tracteurs et véhicules tractés — Partie 2: Couche d'application pour les équipements de freinage et les organes de roulement

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Publication Date
24-Apr-2014
Current Stage
9599 - Withdrawal of International Standard
Completion Date
10-Mar-2023
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INTERNATIONAL ISO
STANDARD 11992-2
Third edition
2014-05-01
Road vehicles — Interchange of digital
information on electrical connections
between towing and towed vehicles —
Part 2:
Application layer for brakes and
running gear
Véhicules routiers — Échange d’informations numériques sur
les connexions électriques entre véhicules tracteurs et véhicules
tractés —
Partie 2: Couche d’application pour les équipements de freinage et les
organes de roulement
Reference number
ISO 11992-2:2014(E)
©
ISO 2014

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ISO 11992-2:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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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
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Tel. + 41 22 749 01 11
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Published in Switzerland
ii © ISO 2014 – All rights reserved

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ISO 11992-2:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 4
5 General Specifications . 4
6 Application layer . 5
6.1 Protocol Data Unit (PDU) specification . 5
6.2 Parameter group number (PGN) . 7
6.3 Address assignment. 7
6.4 Message routing . 9
6.5 Parameters .10
6.6 Messages .57
7 Conformance tests .72
7.1 General .72
7.2 Conformance tests for commercial vehicles .72
7.3 Conformance tests for towed vehicles .73
Annex A (normative) Geometric data .75
Annex B (informative) Message flow .79
Bibliography .83
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ISO 11992-2:2014(E)

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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical
and electronic equipment.
This third edition cancels and replaces the second edition (ISO 11992-2:2003), which has been technically
revised. It also replaces ISO 11992-2:2003/Amd 1:2007.
ISO 11992 consists of the following parts, under the general title Road vehicles — Interchange of digital
information on electrical connections between towing and towed vehicles:
— Part 1: Physical and data-link layers
— Part 2: Application layer for brakes and running gear
— Part 3: Application layer for equipment other than brakes and running gear
— Part 4: Diagnostic communication
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ISO 11992-2:2014(E)

Introduction
This part of ISO 11992 has been established in order to define the data interchange between a commercial
vehicle and its towed vehicle(s), including the communication between towed vehicles, using a Controller
Area Network (CAN) serial data link as specified in ISO 11992-1 for control and status data related to
electronically controlled braking and running gear applications.
It is subject to additions which will become necessary in order to keep pace with experience and technical
advances. Care has been taken to ensure that these additions can be introduced in a compatible way,
and care will have to be taken in the future so that such additions remain compatible with the previous
versions. In particular, it can become necessary to standardize new parameters and parameter groups.
ISO members can request that such new parameters and parameter groups are to be included in the
future editions of ISO 11992.
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INTERNATIONAL STANDARD ISO 11992-2:2014(E)
Road vehicles — Interchange of digital information
on electrical connections between towing and towed
vehicles —
Part 2:
Application layer for brakes and running gear
1 Scope
This part of ISO 11992 specifies the parameters and messages for electronically controlled braking
systems, including anti-lock braking systems (ABS) and vehicle dynamics control systems (VDC), as well
as for running gear equipment (i.e. systems for steering, suspension, and tyres), to ensure that the data
communication interchange of information between road vehicles with a maximum authorized total
mass greater than 3 500 kg and their towed vehicles, including the communication between (several)
towed vehicles, on a dedicated network. It does not include any other communication on that network
that is not related to the communication between those vehicles.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 7638 (all parts), Road vehicles — Connectors for the electrical connection of towing and towed vehicles
ISO 11898-1, Road vehicles — Controller area network (CAN) — Part 1: Data link layer and physical signalling
ISO 11992-1, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 1: Physical and data-link layers
ISO 11992-4, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 4: Diagnostic communication
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11898-1, ISO 11992-1, and the
following apply.
3.1
anti-lock braking system
ABS
control function which automatically modulates the pressure producing the braking forces at the wheels
to limit the degree of wheel slip, or a system that provides an anti-lock braking function
3.2
anti-spin regulation
ASR
control function which automatically modulates the engine torque or the pressure producing the braking
forces at the wheels to limit the degree of wheel spin, or a system that provides an anti-spin control
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ISO 11992-2:2014(E)

3.3
center-axle trailer
towed vehicle equipped with a rigid towing device, and in which the axle(s) is (are) positioned close to
the centre of gravity of the vehicle
3.4
commercial vehicle
motor vehicle which, on account of its design and appointments, is used mainly for conveying goods and
which can also tow a trailer
3.5
converter dolly
dolly unit that couples to a semi-trailer with a fifth-wheel coupling and thereby “converts” the semi-
trailer to a full trailer
3.6
electronic braking system
EBS
braking system in which control is generated and processed as an electrical signal in the control
transmission
3.7
electronic control unit
ECU
electronic item consisting of a combination of basic parts, subassemblies, and assemblies packaged
together as a physically independent entity
3.8
full trailer
towed vehicle equipped with a towing device which can move vertically (in relation to the trailer), and
in which the axle(s) is (are) positioned less close to the centre of gravity of the vehicle
3.9
gateway
unit connecting different networks or parts of one network and performing any necessary protocol
translation
3.10
link trailer
towed vehicle with a fifth-wheel coupling, designed for towing a semi-trailer
3.11
network segment
part of a network that is within the domain of a single link layer
3.12
node
device capable of sending or receiving data whose identification will be unambiguous for authentication
purposes
3.13
running rear equipment
RGE
equipment of a vehicle, including steering, suspension, and tyres
3.14
roll-over prevention/protection
ROP
control function to prevent roll-over situations of a vehicle
Note 1 to entry: ROP is part of a VDC (3.20) function.
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ISO 11992-2:2014(E)

Note 2 to entry: In UNECE Regulation No. 13, roll-over prevention is referred to as “roll-over control”.
3.15
semi-trailer
trailer which is designed to be coupled to a semi-trailer towing vehicle and to impose a substantial part
of its total weight on the towing vehicle
3.16
towed vehicle
non-power-driven road vehicle which, on account of its design and appointments, is used to transport
persons or goods and is intended to be towed by a motor vehicle
3.17
towing full trailer
towed vehicle equipped with a towing device which can move vertically (in relation to the trailer), and
in which the axle(s) is (are) positioned less close to the centre of gravity of the vehicle that is capable of
towing another vehicle
3.18
towing semi-trailer
trailer which is designed to be coupled to a semi-trailer towing vehicle and to impose a substantial part
of its total weight on the towing vehicle that is capable of towing another vehicle
3.19
towing vehicle
motor vehicle or non-power-driven vehicle which tows a succeeding vehicle
3.20
vehicle dynamic control
VDC
control function as part of the braking system that reacts to stabilize the vehicle during dynamic
manoeuvres
Note 1 to entry: VDC has the possible sub-functions ROP (3.14) and YC (3.21).
3.21
yaw control
YC
control function to reduce an unwanted lateral movement of a vehicle
Note 1 to entry: Yaw control is part of a VDC (3.20) function.
Note 2 to entry: In UNECE Regulation No. 13, YC is referred to as “directional control”.
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ISO 11992-2:2014(E)

4 Symbols and abbreviated terms
CAN Controller Area Network
CAN-ID CAN identifier
DA destination address
DLC data length code
DP data page
EDP extended data page
GE group extension
LSB least significant byte (or bit)
MSB most significant byte (or bit)
P priority
PDU Protocol Data Unit
PF PDU format
PGN parameter group number
PS PDU specific
SA source address
TOS type of service
UTC Universal Time Coordinate
5 General Specifications
The data link shall be in accordance with ISO 11898-1. The physical layer shall be in accordance with
ISO 11992-1.
Appropriate PDUs are specified to structure the communication between the towing and towed vehicles’
interface(s). These PDUs shall be transmitted between the electronic devices (nodes) at the towing
vehicle and each towed vehicle, as defined in the following sections.
Each node at a vehicle shall provide logical separation between the network segments and any in-vehicle
networks and act as a gateway to forward the messages, as specified in the following sections.
Any combination of new and old towing and towed vehicles is allowed. Multiple towed vehicles can be
connected in any combination. The network shall be capable of addressing any towed vehicle, including
dollies. The truck operator can disconnect and connect towed vehicles at any time and any order, and the
network shall adjust and respond accordingly.
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ISO 11992-2:2014(E)

6 Application layer
6.1 Protocol Data Unit (PDU) specification
6.1.1 General
The application layer provides a string of information that is assembled as a PDU. The PDU provides a
framework for organizing the information sent by means of CAN data frames.
All transmitted CAN data frames shall use the extended data frame format with a 29-bit CAN-ID as
defined in ISO 11898-1. The PDU framework for the normal and diagnostic communications between the
commercial vehicles and towed vehicles is the same as defined in Reference [1] and is specified in 6.1.2.
Diagnostic communication between the towed vehicles shall use the subnet addressing PDU format as
specified in 6.1.3.
6.1.2 PDU format for normal communication and diagnostic communication (PDU1 and PDU2)
The PDU1 and PDU2 shall consist of the following fields as shown in Figure 1:
— a 29-bit CAN-ID with the subfields priority (P), extended data page (EDP), data page (DP), PDU
format (PF), PDU specific (PS) [which can be a destination address (DA) or a group extension (GE)],
and source address (SA);
— a 64-bit data field.
Figure 1 — PDU1 and PDU2 structure
Depending on the contents of the subfields, the PDUs are classified as PDU1 or PDU2 frames as given in
the following definitions.
6.1.3 PDU format for subnet addressing communication (PDU3)
The PDU3 shall consist of the following fields as shown in Figure 2:
— a 29-bit CAN-ID with the subfields priority (P), extended data page (EDP), data page (DP), type of
service (TOS), destination address (DA) and source address (SA);
— a 64-bit data field.
Figure 2 — PDU3 structure
The fields P, EDP, and DP shall be used as given in the following definitions. All other fields shall be used
as defined in ISO 11992-4.
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ISO 11992-2:2014(E)

6.1.4 Priority (P)
This 3-bit subfield shall be used to optimize the PDU frame latency for transmission onto the bus only
and shall have no other specific meaning. It shall not be used for message validation on the receiver side
and should be globally masked off by the receiver (ignored). The priority of any PDU can be set from
highest, 0 (000 ), to lowest, 7 (111 ), and will use the following default values.
10 2 10 2
— The default for all control-oriented PDUs shall be 3 (011 ).
10 2
— The default of all other informational PDUs shall be 6 (110 ).
10 2
— The default for diagnostic PDUs shall be 7 (111 ).
10 2
6.1.5 Extended data page (EDP)
This 1-bit subfield shall be used in conjunction with the DP subfield to select an auxiliary range of PGNs
or to select subnet addressing diagnostic messages. The definition of a PGN is given in 6.2. The definition
of CAN frames for subnet addressing diagnostic messages is given in 6.6.
6.1.6 Data page (DP)
This 1-bit subfield shall be used in conjunction with the EDP subfield to select an auxiliary range of PGNs
or to select subnet addressing diagnostic messages. The definition of a PGN is given in 6.2. The definition
of CAN frames for subnet addressing diagnostic messages is given in 6.6.
6.1.7 PDU format (PF)
This 8-bit subfield shall determine the PDU format and the transmission method as specified in Table 1.
— If the value of the PDU format field is below 240, then the PDU format is of type PDU1 and the PDU-
specific field contains a destination address.
— If the value of the PDU format field is 240 to 255, then the PDU format is of type PDU2 and the PDU-
specific field contains a group extension.
Table 1 — PDU definition
PF value PDU format PS Transmission method
0 to 239 PDU1 DA This PDU 1 format shall be used for messages to be sent directly to either a
specific or a global destination.
240 to 255 PDU2 GE This PDU 2 format shall only be used to communicate global (broadcast)
messages.
6.1.8 PDU specific (PS)
6.1.8.1 General
This 8-bit subfield shall depend on the PDU format. For a PDU1 format, the PDU specific (PS) subfield is
a destination address (DA), for a PDU2 format, the PS subfield is a group extension (GE) (see Table 1).
6.1.8.2 Destination address (DA)
The DA shall contain the specific address of the towing or towed vehicle to which the PDU is being sent.
If the global destination address (255 = FF ) is sent, all nodes shall process the PDU.
10 16
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ISO 11992-2:2014(E)

6.1.8.3 Group extension (GE)
The GE in conjunction with the four least significant bits of the PF subfield shall be used as part of the
specific PGN.
6.1.9 Source address (SA)
This 8-bit subfield shall provide the source address (SA) of the node that transmits the PDU. Therefore
the SA subfield ensures that the CAN-ID is unique on all network segments.
6.1.10 Data field
All CAN data frames shall use a data field length of 8 byte, i.e. DLC = 8. If less than 8 byte are required by
the defined PGN, all non-used bits shall be transmitted with all bits set to “1”.
6.2 Parameter group number (PGN)
This 24-bit number shall be used in all cases where a group of parameters assembled in the PDU1 or
PDU2 data field needs to be identified. A PGN is built from the CAN-ID subfields EDP, DP, PF, and PS
as specified in Figure 3 and is used to identify or label a group of parameters. It is independent of the
remaining fields of the CAN-ID.
The upper bits 18 to 23 are reserved and shall always be set to zero (0). For a PDU1 message, i.e. if the PS
field is a DA, the least significant byte (LSB) of the PGN shall always be set to zero (0).
Figure 3 — PGN subfield definition
NOTE To reduce the effort of exchanging PDUs between the ISO 11992-2 communication and any in-vehicle
network, the PGNs within this International Standard are harmonized with those used in SAE J1939.
EXAMPLE For a message with CAN-ID 18FEC920 (PDU2 format), the subfields are P = 110 , EDP = 0 ,
16 2 2
DP = 0 , PF = FE , PS = C9 , and SA = 20 . The corresponding PGN is 00FEC9 (65225 ).
2 16 16 16 16 10
6.3 Address assignment
6.3.1 Address usage
A road train consists of one truck (commercial vehicle) and one or more trailer(s) (towed vehicles).
Dollies within the road train shall be treated as additional towed vehicles (see Figure 4).
The commercial vehicle is the towing vehicle of towed vehicle #1; towed vehicle #1 is the towing vehicle
of towed vehicle #2; and so on.
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ISO 11992-2:2014(E)

Key
1 truck/commercial vehicle (position #0) 3 converter dolly/towed vehicle position #2
2 trailer/towed vehicle position #1 4 trailer/towed vehicle position #3
Figure 4 — Example of a possible road train configuration
For the towing vehicle/towed vehicle communication, each node shall use only the addresses given in
Table 2 as SA and DA for all messages.
Table 2 — Commercial vehicle/towed vehicle addresses
Name Address Predecessor Successor
commercial vehicle (#0) 32 / 20 n/a towed vehicle #1
10 16
towed vehicle #1 200 / C8 commercial vehicle (#0) towed vehicle #2
10 16
towed vehicle #2 192 / C0 towed vehicle #1 towed vehicle #3
10 16
towed vehicle #3 184 / B8 towed vehicle #2 towed vehicle #4
10 16
towed vehicle #4 176 / B0 towed vehicle #3 towed vehicle #5
10 16
towed vehicle #5 168 / A8 towed vehicle #4 undefined
10 16
global destination address 255 / FF undefined undefined
10 16
The global destination address shall only be used by the commercial vehicle to broadcast information to
all the towed vehicles simultaneously.
6.3.2 Address assignment procedure
The address of the commercial vehicle is fixed. The respective address of a towed vehicle corresponds
to its position within the road train and shall be (re)assigned each time
— a communication starts or
— the towed vehicle has been connected to the road train.
The dynamic address assignment shall be handled by the respective towing/towed vehicle’s node
and concerns the determination of the individual position within the road train. It is based on the
transmission of the general initialization message (see 6.6.4.1) by the respective predecessor within the
road train.
Within a road train, the address assignment procedure shall be initiated by the commercial vehicle,
using its default address for the general initialization message. A powered-up towed vehicle’s node shall
use the address of towed vehicle #1 as the default address for transmitting the available information
until the general initialization message has been received from the towing vehicle and a valid address
can be assigned.
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ISO 11992-2:2014(E)

Each towed vehicle’s node shall use the general initialization message received at the towing vehicle’s
network interface to determine its own address. It shall use the successor’s address of that message’s SA
as its own address. This requires that a towed vehicle’s node shall be capable of
— identifying its predecessor by the SA of the general initialization message,
— assigning its own address based on the predecessors address, and
— identifying the potential receiver(s) by the destination address and by the message type.
An assigned address shall be valid as long as the towed vehicle is powered and no message from the
predecessor with a different SA is received. If a different SA is received, the assignment procedure shall
be restarted.
To provide the address assignment for itself and for possible successors, a node shall be capable
of continuously sending the general initialization message with its dynamically assigned own SA as
illustrated in Figure 5.
This addressing method allows the towed vehicle’s node to communicate and to identify its presence
to its predecessor immediately after power-up. This means that several towed vehicles can use the
same address until the address assignment procedure is completed. Continuous sending of the general
initialization message is necessary to allow immediate towed vehicle address assignment at any time a
towed vehicle should be connected.
Figure 5 — Address assignment procedure
6.4 Message routing
If a vehicle has no provision for a successor, the message routing function is not required by the vehicle’s
node.
To allow communication between the towing and towed vehicles, a node shall be capable of
— receiving messages from its predecessor and successor within the road train,
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ISO 11992-2:2014(E)

— identifying receiver(s) by the destination address (PDU 1 type messages) or the PDU format (PDU 2
type messages),
— routing all applicable messages from its predecessor(s) to its successor(s) within the road train
by sending them with the unchanged SA and DA to its successor within a maximal delay time of
t = 13 ms, and
d
— routing all applicable messages from its successor(s) to its predecessor(s) within the road train
by sending them with the unchanged SA and DA to its predecessor within a maximal delay time of
t = 13 ms.
d
A towed vehicle node shall not route messages to its successor or predecessor within the road train
— if the SA of a message received from its predecessor corresponds to a road train position closer or
equal to its own from the commercial vehicle or
— if the SA of a message received from its successor corresponds to a road train position more distant
or equal to its own from the commercial vehicle.
EXAMPLE Figure 6 shows some examples of the message flow between vehicles.
Figure 6 — Example of the message flow between vehicles
6.5 Parameters
6.5.1 Generic data ranges
Each defined parameter shall comply with one of the defined parameter types.
— Table 3 specifies the ranges used to determine the validity of the transmitted signals.
— Table 4 specifies the ranges used to denote the status of a discrete parameter.
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ISO 11992-2:2014(E)

— Table 5 specifies the ranges used to denote the status of a control mode command.
The values in the range “error indicator” provide a means for a module to immediately indicate that valid
parameter data are not currently available, owing to some type of error in the sensor, subsystem, or
module. Additional information about the failure can be obtained using the diagnostic communication.
The values in the range “not available” provide a means for a module to transmit a parameter that is not
available or not supported in that module. This value does not replace the “error indicator”.
The values in the range “not requested” provide a means for a device to transmit a command message
and identify those parameters where no response is expected from the receiving device.
The values in the range of “special function” are reserved for the definition of parameter-specific
functionalities.
For some parameters, non-generic definitions are given in the following sections. These are not defined
here. Examples are encoded table values, where each value is assigned to one specific meaning.
After power-on,
...

DRAFT INTERNATIONAL STANDARD ISO/DIS 11992-2
ISO/TC 22/SC 3 Secretariat: DIN
Voting begins on Voting terminates on

2011-12-12 2012-15-12
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION  •  МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ  •  ORGANISATION INTERNATIONALE DE NORMALISATION


Road vehicles — Interchange of digital information on electrical
connections between towing and towed vehicles —
Part 2:
Application layer for brakes and running gear
Véhicules routiers -- Échange d'informations numériques sur les connexions électriques entre véhicules
tracteurs et véhicules tractés —
Partie 2: Couche d'application pour les équipements de freinage et les organes de roulement
[Revision of second edition (ISO 11992-2:2003) and ISO 11992-2:2003/Amd.1:2007]
ICS 43.040.15






In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est
distribué en version anglaise seulement.

To expedite distribution, this document is circulated as received from the committee
secretariat. ISO Central Secretariat work of editing and text composition will be undertaken at
publication stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.



THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
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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 SUPPORTING DOCUMENTATION.
©  International Organization for Standardization, 2011

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ISO/DIS 11992-2

Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted
under the applicable laws of the user’s country, neither this ISO draft nor any extract from it may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic,
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Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.

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ISO/DIS 11992-2
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 General Specifications . 4
6 Application layer . 5
6.1 Protocol Data Unit (PDU) specification . 5
6.2 Parameter Group Number (PGN) . 7
6.3 Address assignment . 7
6.4 Message routing . 9
6.5 Parameters . 11
6.6 Messages . 63
7 Conformance tests . 82
7.1 General . 82
7.2 Conformance tests for commercial vehicles . 82
7.3 Conformance tests for towed vehicles . 83
Annex A (normative) Geometric data . 84
Annex B (informative) Message Flow . 88
Bibliography . 94

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ISO/DIS 11992-2
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11992-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
This third edition cancels and replaces the second edition (ISO 11992-2:2003) and its amendment 1 of which
have been technically revised.
ISO 11992 consists of the following parts, under the general title Road vehicles — Interchange of digital
information on electrical connections between towing and towed vehicles:
⎯ Part 1: Physical layer and data-link layer
⎯ Part 2: Application layer for brakes and running gear
⎯ Part 3: Application layer for equipment other than brakes and running gear
⎯ Part 4: Diagnostics
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ISO/DIS 11992-2
Introduction
This part of the internation standard has been established in order to define the data interchange between a
commercial vehicle and its towed vehicle(s), including communication between towed vehicles, using a
Controller Area Network (CAN) serial data link as specified in ISO 11992-1 for control and status data related
to electronical controlled braking and running gear applications.
It is subject to additions which will become necessary in order to keep pace with experience and technical
advances. Care has been taken to ensure that these additions can be introduced in a compatible way, and
care will have to be taken in the future so that such additions remain compatible with previous versions. In
particular, it may become necessary to standardize new parameters and parameter groups. ISO members can
request that such new parameters and parameter groups to be included in future editions of ISO 11992.

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DRAFT INTERNATIONAL STANDARD ISO/DIS 11992-2

Road vehicles — Interchange of digital information on electrical
connections between towing and towed vehicles —
Part 2:
Application layer for brakes and running gear
1 Scope
This part of the ISO 11992 international standard specifies the parameters and messages for electronically
controlled braking systems, including ABS (anti-lock braking systems) and VDC (vehicle dynamics control
systems) as well as for running gear equipment (i.e. systems for steering, suspension and tyres), to ensure
the data communication interchange of information between road vehicles with a maximum authorized total
mass greater than 3500 kg, and their towed vehicles, including the communication between (several) towed
vehicles, on a dedicated network. It does not include any other communication on that network that is not
related to communication between those vehicles.
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.
ISO 7638, Road vehicles — Connectors for the electrical connection of towing and towed vehicles —
Connectors for braking systems and running gear of vehicles
ISO 11898-1, Road vehicles — Controller area network (CAN) — Part 1: Data link layer and physical
signalling
ISO 11992-1, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 1: Physical layer and data-link layer
ISO 11992-4, Road vehicles — Interchange of digital information on electrical connections between towing
and towed vehicles — Part 4: Diagnostics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11992-1, ISO 11898-1 and the
following apply.
3.1
ABS
This definition is used for a control function to support anti-lock braking (anti-lock braking system). It is also
used for control systems providing an anti-lock braking function.
3.2
ASR
This definition is used for a control function to support traction control (anti-spin regulation).
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3.3
Centre-axle trailer
This term is used for a towed vehicle equipped with a towing device which can not move vertically (in relation
to the trailer), and in which the axle(s) is(are) positioned close to the center of gravity of the trailer.
3.4
Commercial vehicle
This term is used for a vehicle that is engine driven and capable of towing other vehicles; same as a truck or
tractor.
3.5
EBS
This definition is used for a control system providing an electronically controlled braking that contains
functions like ABS, ASR, VDC.
3.6
ECU
This term is used for an electronic control unit.
3.7
Drawbar trailer
This term is used for a towed vehicle with one axle group or single axle at the front that is steered by
connection to the towing vehicle by a drawbar and one axle group or single axle at the rear. This vehicle may
also be a towing type.
3.8
Dolly
This term is used for a towed vehicle with one axle group or single axle, and a fifth wheel coupling, designed
to convert a semi trailer into the equivalent of a full trailer.
3.9
Gateway
This term is used for a network node that is able to filter and forward messages to different network segments.
3.10
Link trailer
This term is used for a towed vehicle with a fifth wheel coupling, designed for towing a semi trailer.
3.11
Network segment
This term is used for an electrical connection between one group of logically combined nodes of a
communication network.
3.12
Node
This term is used for an electronic device providing means to receive and transmit messages.
3.13
RGE
This definition is used for running gear equipment of a vehicle, including steering, suspension and tyres.
3.14
ROP
This definition is used for a control function to prevent roll-over situations of a vehicle (roll-over prevention /
protection), part of a VDC function.
NOTE In UNECE Regulation No. 13 Roll-over Prevention is referred to as Roll-over Control.
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ISO/DIS 11992-2
3.15
Semi-trailer
This term is used for a towed vehicle with one axle group or single axle at the rear and a means of attachment
to a tractor that results in some of the load being imposed on the tractor.
3.16
Towed vehicle

This term is used for any type of vehicle that is actually being towed by another vehicle; usually these are
trailers or dollies.
3.17
Towing vehicle

This term is used for any type of vehicle that is actually towing another vehicle; usually these are commercial
vehicles (tractors) or a trailer or dolly towing another trailer
3.18
VDC
This definition is used for a control function as part of the braking system that reacts to stabilise the vehicle
during dynamic manoeuvres (Vehicle Dynamic Control) with the possible sub-functions ROP, YC.
3.19
YC
This definition is used for a control function to reduce unwanted lateral movement of a vehicle (yaw control),
part of a VDC function
NOTE In UNECE Regulation No. 13 Yaw Control is referred to as Directional Control.
4 Symbols and abbreviated terms
CAN Controller Area Network
CAN-ID CAN Identifier
DA Destination Address
DLC Data Length Code
DP Data Page
EDP Extended Data Page
GE Group Extension
LSB Least Significant Byte (or Bit)
MSB Most Significant Byte (or Bit)
P Priority
PDU Protocol Data Unit
PF PDU Format
PGN Parameter Group Number
PS PDU Specific
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ISO/DIS 11992-2
SA Source Address
UTC Universal Time Coordinate
5 General Specifications
The data link shall be in accordance with ISO 11898-1; the physical layer shall be in accordance with
ISO 11992-1.
Appropriate PDUs are specified to structure the communication between towing and towed vehicle
interface(s). These PDUs shall be transmitted between electronic devices (nodes) at the towing vehicle and
each towed vehicle as defined in the following sections.
Each node at a vehicle shall provide logical separation between the network segments and any in-vehicle
networks and act as a gateway to forward the messages as specified in the following sections.
Any combination of new and old towing and towed vehicles is allowed. Multiple towed vehicles may be
connected in any combination; the network shall be capable of addressing any towed vehicle, including
dollies. The truck operator may disconnect and connect towed vehicles at any time and any order and the
network shall adjust and respond accordingly.
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ISO/DIS 11992-2
6 Application layer
6.1 Protocol Data Unit (PDU) specification
6.1.1 General
The application layer provides a string of information that is assembled as a PDU. The PDU provides a
framework for organizing the information sent by means of CAN data frames.
All transmitted CAN data frames shall use the extended data frame format with a 29-bit CAN-ID as defined in
ISO 11898-1. The PDU framework is the same as defined in SAE J1939-71 [2].
The PDU shall consist of the fields as shown in Figure 1, which are
⎯ a 29-bit CAN-ID with the sub-fields Priority (P), Extended Data Page (EDP), Data Page (DP), PDU
Format (PF), PDU Specific (PS) — which may be a Destination Address (DA) or a Group
Extension (GE) —, and Source Address (SA),
⎯ a 64-bit data field.
MSB 29-bit CAN-ID bit position LSB CAN data field byte position
bit/byte
28 26 25 24 23 16 15 8 7 0 1 2 3 4 5 6 7 8
position

Data field
P EDP DP PF PS SA

number
3 1 1 8 8 8 64
of bits
Figure 1 — PDU structure
Depending on the contents of the sub-fields the PDUs are classified as PDU1 or PDU2 frames as given in the
following definitions.
6.1.2 Priority (P)
This 3-bit sub-field shall be used to optimize PDU frame latency for transmission onto the bus only and shall
have no other specific meaning. It shall not be used for message validation on receiver side and should be
globally masked off by the receiver (ignored). The priority of any PDU may be set from highest, 0 (000 ), to
10 2
lowest, 7 (111 ) and will use this default values:
10 2
⎯ The default for all control oriented PDUs shall be 3 (011 ).
10 2
⎯ The default of all other informational PDUs shall be 6 (110 ).
10 2
⎯ The default for diagnostic PDUs shall be 7 (111 ).
10 2
6.1.3 Extended Data Page (EDP)
This 1-bit sub-field shall be used in conjunction with the DP sub-field to select an auxiliary range of PGNs. The
definition of a PGN is given in clause 6.2. This bit shall always be set to zero.
6.1.4 Data Page (DP)
This 1-bit sub-field shall be used to select an auxiliary range of PGNs. The definition of a PGN is given in
clause 6.2.
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ISO/DIS 11992-2
6.1.5 PDU Format (PF)
This 8-bit sub-field shall determine the PDU format and the transmission method as specified in Table 1.
⎯ If the value of the PDU format field is below 240, then the PDU format is of type PDU1 and the PDU-
specific field contains a destination address.
⎯ If the value of the PDU format field is 240 to 255, then PDU format is of type PDU2 and the PDU-specific
field contains a group extension.
Table 1 — PDU definition
PDU
PF value PS Transmission method
format
This PDU 1 format shall be used for messages to be sent directly to either a
0 to 239 PDU1 DA
specific or a global destination.
This PDU 2 format shall only be used to communicate global (broadcast)
240 to 255 PDU2 GE
messages.

6.1.6 PDU Specific (PS)
6.1.6.1 General
This 8-bit sub-field shall depend on the PDU format. For a PDU1 format the PDU specific (PS) sub-field is a
destination address (DA), for a PDU2 format the PS sub-field is a group extension (GE) (see Table 1).
6.1.6.2 Destination Address (DA)
The DA shall contain the specific address of the towing or towed vehicle to which the PDU is being sent. If the
global destination address (255 = FF ) is sent, all nodes shall process the PDU.
10 16
6.1.6.3 Group Extension (GE)
The GE in conjunction with the four least significant bits of the PF sub-field shall be used as part of the
specific PGN.
6.1.7 Source Address (SA)
This 8-bit sub-field shall provide the source address (SA) of the node that transmits the PDU. Therefore the
SA sub-field assures that the CAN-ID is unique on all network segments.
6.1.8 Data field
All CAN data frames shall use a data field length of 8 byte, i.e. DLC=8. If less than 8 byte are required by the
defined PGN all non-used bits shall be transmitted with all bits set to 1.
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ISO/DIS 11992-2

6.2 Parameter Group Number (PGN)
This 24-bit number shall be used in all cases where a group of parameters assembled in the PDU data field
need to be identified. A PGN is built from the CAN-ID sub-fields EDP, DP, PF and PS as specified in Figure 2
and is used to identify or label a group of parameters. It is independent of the remaining fields of the CAN-ID.
The upper bits 18 to 23 are reserved and shall always be set to zero (0). For a PDU1 message, i.e. if the PS
field is a DA, the least significant byte (PS) of the PGN shall always be set to zero (0).
MSB    LSB
byte position 2 1 0
bit position 23 18 17 16 15 8 7 0
000000 EDP DP PF PS
2
Number of bits 6 1 1 8 8
Figure 2 — PGN sub-field definition
NOTE To reduce the effort of exchanging PDUs between the ISO 11992-2 communication and any in-vehicle
network, the PGNs within this standard are harmonized with those used in SAE J1939.
EXAMPLE For a message with CAN-ID 18FEC920 (PDU2 format) the sub-fields are P= 110 , EDP= 0 , DP= 0 ,
16 2 2 2
PF= FE , PS= C9 , SA= 20 . The corresponding PGN is 00FEC9 (65225 ).
16 16 16 16 10
6.3 Address assignment
6.3.1 Address usage
A road-train consists of one truck (commercial vehicle) and one or more trailer(s) (towed vehicles). Dollies
within the road train shall be treated as additional towed vehicles (see Figure 3).
The commercial vehicle is the towing vehicle of towed vehicle #1; towed vehicle #1 is the towing vehicle of
towed vehicle #2; and so on.
12 3 4

Key:
1 truck / commercial vehicle (position #0)
2 trailer / towed vehicle position #1
3 dolly / towed vehicle position #2
4 trailer / towed vehicle position #3
Figure 3 — Example of a possible road train configuration

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ISO/DIS 11992-2
For towing vehicle/towed vehicle communication, each node shall use only the addresses given in Table 2 as
SA and DA for all messages.
Table 2 — Commercial vehicle / towed vehicle addresses
name address predecessor successor
commercial vehicle (#0) 32 / 20 n/a towed vehicle #1
10 16
towed vehicle #1 200 / C8 commercial vehicle (#0) towed vehicle #2
10 16
towed vehicle #2 192 / C0 towed vehicle #1 towed vehicle #3
10 16
towed vehicle #3 184 / B8 towed vehicle #2 towed vehicle #4
10 16
towed vehicle #4 176 / B0 towed vehicle #3 towed vehicle #5
10 16
towed vehicle #5 168 / A8 towed vehicle #4 undefined
10 16
global destination address 255 / FF undefined undefined
10 16

The global destination address shall only be used by the commercial vehicle to broadcast information to all
towed vehicles simultaneously.
6.3.2 Address assignment procedure
The address of the commercial vehicle is fixed. The respective address of a towed vehicle corresponds to its
position within the road train and shall be (re-) assigned each time
⎯ communication starts, or
⎯ the towed vehicle has been connected to the road train.
The dynamic address assignment shall be handled by the respective towing vehicle/towed vehicle node and
concerns the determination of the individual position within the road train. It is based on transmission of the
general initialization message (see clause 6.6.4.1) by the respective predecessor within the road-train.
Within a road-train, the address assignment procedure shall be initiated by the commercial vehicle, using its
default address for the general initialization message. A powered-up towed vehicle node shall use the towed
vehicle #1 address as the default address for transmitting available information until the general initialization
message has been received from the towing vehicle and a valid address can be assigned.
Each towed vehicle node shall use the general initialization message received at the towing vehicle network
interface to determine its own address. It shall use the successor's address of that message's SA as its own
address. This requires that a towed vehicle node shall be capable of
⎯ identifying its predecessor by the SA of the general initialization message,
⎯ assigning its own address based on the predecessors address, and
⎯ identifying potential receiver(s) by the destination address and by the message type.
An assigned address shall be valid as long as the towed vehicle is powered and no message from the
predecessor with a different SA is received. If a different SA is received the assignment procedure shall be
restarted.
To provide address assignment for itself and for possible successors, a node shall be capable of continuously
sending the general initialization message with its dynamically assigned own SA as illustrated in Figure 4.
This addressing method allows the towed vehicle node to communicate and to identify its presence to its
predecessor immediately after power-up. This means that several towed vehicles can use the same address
until the address assignment procedure is completed. Continuous sending of the general initialization
message is necessary to allow immediate towed vehicle address assignment at any time a towed vehicle
might be connected.
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ISO/DIS 11992-2
Commercial vehicle Trailer #1 Trailer #2 Trailer #3 Trailer #4 Trailer #5
Sends SA=commercial vehicle to sucessor
SA =
Commercial
Receives SA = commercial vehicle from pred.
vehicle
Claims SA = towed vehicle #1
Sends SA = Towed vehicle #1 to successor
SA =
Towed
Receives SA = towed vehicle #1 from pred.
vehicle #1
Claims SA = towed vehicle #2
Sends SA = Towed vehicle #2 to successor
SA =
Receives SA = toved vehicle #2 from pred. Towed
Caims SA = towed vehicle #3 vehicle #2
Sends SA = Towed vehicle #3 to successor
SA =
Receives SA = towed vehicle #3 from pred.
Towed
Claims SA = towed vehicle #4
vehicle #3
Sends SA = Towed vehicle #4 to successor
SA =
Receives SA = towed vehicle #4 from pred. Towed
Claims SA = towed vehicle #5
vehicle #4

Figure 4 — Address assignment procedure

6.4 Message routing
If a vehicle has no provision for a successor, the message routing function is not required by the vehicle's
node.
To allow communication between towing and towed vehicles, a node shall be capable of
⎯ receiving messages from its predecessor and successor within the road-train,
⎯ identifying receiver(s) by the destination address (PDU 1 type messages) or the PDU format (PDU 2 type
messages),
⎯ routing all applicable messages from its predecessor(s) to its successor(s) within the road-train by
sending them with the unchanged SA and DA to its successor within a maximal delay time of t = 13 ms,
d
⎯ routing all applicable messages from its successor(s) to its predecessor(s) within the road-train by
sending them with the unchanged SA and DA to its predecessor within a maximal delay time of
= 13 ms.
t
d
A towed vehicle node shall not route messages to its successor or predecessor within the road-train,
⎯ if the SA of a message received from its predecessor corresponds to a road-train position closer or equal
to its own to the commercial vehicle, or
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ISO/DIS 11992-2
⎯ if the SA of a message received from its successor corresponds to a road-train position more distant or
equal to its own from the commercial vehicle.
EXAMPLE Figure 5 shows some examples of message flow between vehicles

Commercial vehicle Towed vehicle #1 Towed vehicle #2 Towed vehicle #3
PDU 1 type messages from towing
vehicles to succeeding towed
vehicles
PF = PF =
PF =
PS = DA[towed vehicle #2] PS = DA[towed vehicle #3]
PS = DA[towed vehicle #1]
SA = commercial vehicle SA = towed vehicle #1 SA = towed vehicle #2
PDU 1 type message from
PF =
commercial vehicle to towed vehicle
PS = DA[towed vehicle #2]
PF =
#2
SA = commercial vehicle No transmission
PS = DA[towed vehicle #2]
SA = commercial vehicle
PDU 2 type message from PF =
PF =
commercial vehicle to all towed PS =
PS =
vehicles SA = commercial vehicle
PF =
SA = commercial vehicle
PS =
SA = commercial vehicle
PDU 1 type messages from towed
vehicles to preceding towing vehicles
PF = PF = PF =
PS = DA[commercial vehicle] PS = DA[towed vehicle #1] PS = DA[towed vehicle #2]
SA = towed vehicle #1 SA = towed vehicle #2 SA = towed vehicle #3
PF =
PF =
PS = DA[commercial vehicle]
PDU 1 type message from towed
PS = DA[commercial vehicle]
SA = towed vehicle #3
vehicle #3 to commercial vehicle
PF =
SA = towed vehicle #3
PS = DA[commercial vehicle]
SA = towed vehicle #3
PDU 2 type message from towed
PF =
vehicle #2
PS = No transmission
PF =
SA = towed vehicle #2
PS =
SA = towed vehicle #2

Figure 5 — Example of message flow between vehicles

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ISO/DIS 11992-2

6.5 Parameters
6.5.1 Generic data ranges
Each defined parameter shall comply with one of the defined parameter types
⎯ Table 3 specifies the ranges used to determine the validity of t
...

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