ISO 21806-10:2021
(Main)Road vehicles — Media Oriented Systems Transport (MOST) — Part 10: 150-Mbit/s coaxial physical layer
Road vehicles — Media Oriented Systems Transport (MOST) — Part 10: 150-Mbit/s coaxial physical layer
This document specifies the 150-Mbit/s coaxial physical layer for MOST (MOST150 cPHY), a synchronous time-division-multiplexing network. This document specifies the applicable constraints and defines interfaces and parameters, suitable for the development of products based on MOST150 cPHY. Such products include coaxial links, coaxial receivers, coaxial transmitters, electrical to coaxial converters, and coaxial to electrical converters. This document also establishes basic measurement techniques and actual parameter values for MOST150 cPHY.
Véhicules routiers — Système de transport axé sur les médias — Partie 10: Couche coaxiale physique à 150-Mbit/s
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INTERNATIONAL ISO
STANDARD 21806-10
First edition
2021-05
Road vehicles — Media Oriented
Systems Transport (MOST) —
Part 10:
150-Mbit/s coaxial physical layer
Véhicules routiers — Système de transport axé sur les médias —
Partie 10: Couche coaxiale physique à 150-Mbit/s
Reference number
ISO 21806-10:2021(E)
©
ISO 2021
---------------------- Page: 1 ----------------------
ISO 21806-10:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 21806-10:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
4.1 Symbols . 2
4.2 Abbreviated terms . 2
5 Conventions . 3
6 Physical layer service interface to OSI data link layer . 3
6.1 Overview . 3
6.2 Data type definitions . 3
6.3 Event indications and action requests . 3
6.3.1 P_EVENT.INDICATE . 3
6.3.2 P_ACTION.REQUEST . 4
6.4 Parameters . 4
6.4.1 PHY_Event . 4
6.4.2 PHY_Request . . 4
7 Basic physical layer requirements . 5
7.1 Logic terminology . 5
7.1.1 Single-ended low-voltage digital signals . 5
7.1.2 Differential LVDS signals . 5
7.2 Specification points (SPs) . 5
7.3 Phase variation . 6
7.3.1 General. 6
7.3.2 Wander . 6
7.3.3 Jitter . 6
7.3.4 Clock recovery and reference clock . 7
7.3.5 Link quality . 8
7.3.6 MOST network quality .10
8 MOST150 cPHY requirements .13
8.1 General MOST network parameters .13
8.1.1 MOST network coding .13
8.1.2 Link and interconnect type .14
8.1.3 SP details . . .15
8.1.4 Analogue frontend .16
8.1.5 Integration of coaxial transceiver.17
8.2 Models and measurement methods .19
8.2.1 Golden PLL .19
8.2.2 Jitter filter .20
8.2.3 Retimed bypass mode and stress pattern .21
9 Link specifications .21
9.1 General .21
9.2 SP1 .21
9.3 SP2 .22
9.4 Coaxial link requirements .23
9.4.1 Coaxial interconnect, length and attenuation .23
9.4.2 Characteristic impedance and return loss (L ) .26
RL
9.5 SP3 .30
9.6 SP4 .30
© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 21806-10:2021(E)
10 Power-on and power-off .31
10.1 Frequency reference and power supply .31
10.2 Power supply monitoring circuitry .32
10.3 Coaxial transceiver ECC and CEC .32
10.3.1 General.32
10.3.2 CTR requirements .32
10.3.3 ECC requirements .32
10.3.4 ECC power-on and power-off sequence .35
10.3.5 CEC requirements .35
10.3.6 CEC power-on and power-off sequence.37
11 MOST network requirements .38
11.1 SP4 receiver tolerance .38
11.2 TimingMaster delay tolerance .39
11.3 Environmental requirements and considerations .39
12 Electrical interfaces .39
12.1 LVDS .39
12.2 Bit rate and frequency tolerance .40
13 MOST150 cPHY topologies .40
13.1 Daisy chain topologies .40
13.2 Daisy chain structure .42
13.3 2-port nodes .42
13.4 Port1 delay drift .43
14 Device connectors .46
15 SPs for cable extensions .46
16 Coaxial interconnect attenuation .47
Bibliography .49
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 21806-10:2021(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 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.
A list of all parts in the ISO 21806 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.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 21806-10:2021(E)
Introduction
The Media Oriented Systems Transport (MOST) communication technology was initially developed at
the end of the 1990s in order to support complex audio applications in cars. The MOST Cooperation was
founded in 1998 with the goal to develop and enable the technology for the automotive industry. Today,
1)
MOST enables the transport of high quality of service (QoS) audio and video together with packet data
and real-time control to support modern automotive multimedia and similar applications. MOST is a
function-oriented communication technology to network a variety of multimedia devices comprising
one or more MOST nodes.
Figure 1 shows a MOST network example.
Figure 1 — MOST network example
The MOST communication technology provides:
— synchronous and isochronous streaming,
— small overhead for administrative communication control,
— a functional and hierarchical system model,
— API standardization through a function block (FBlock) framework,
— free partitioning of functionality to real devices,
— service discovery and notification, and
[2]
— flexibly scalable automotive-ready Ethernet communication according to ISO/IEC/IEEE 8802-3 .
MOST is a synchronous time-division-multiplexing (TDM) network that transports different data types
on separate channels at low latency. MOST supports different bit rates and physical layers. The network
clock is provided with a continuous data signal.
1) MOST® is the registered trademark of Microchip Technology Inc. This information is given for the convenience
of users of this document and does not constitute an endorsement by ISO.
vi © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 21806-10:2021(E)
Within the synchronous base data signal, the content of multiple streaming connections and control
data is transported. For streaming data connections, bandwidth is reserved to avoid interruptions,
collisions, or delays in the transport of the data stream.
MOST specifies mechanisms for sending anisochronous, packet-based data in addition to control data
and streaming data. The transmission of packet-based data is separated from the transmission of
control data and streaming data. None of them interfere with each other.
A MOST network consists of devices that are connected to one common control channel and packet
channel.
In summary, MOST is a network that has mechanisms to transport the various signals and data streams
that occur in multimedia and infotainment systems.
The ISO Standards Maintenance Portal (https:/ standards .iso .org/ iso/ ) provides references to MOST
specifications implemented in today's road vehicles because easy access via hyperlinks to these
specifications is necessary. It references documents that are normative or informative for the MOST
versions 4V0, 3V1, 3V0, and 2V5.
The ISO 21806 series has been established in order to specify requirements and recommendations
for implementing the MOST communication technology into multimedia devices and to provide
conformance test plans for implementing related test tools and test procedures.
To achieve this, the ISO 21806 series is based on the open systems interconnection (OSI) basic reference
[1] [3]
model in accordance with ISO/IEC 7498-1 and ISO/IEC 10731, which structures communication
systems into seven layers as shown in Figure 2. Stream transmission applications use a direct stream
data interface (transparent) to the data link layer.
© ISO 2021 – All rights reserved vii
---------------------- Page: 7 ----------------------
ISO 21806-10:2021(E)
Figure 2 — The ISO 21806 series reference according to the OSI model
The International Organization for Standardization (ISO) draws attention to the fact that it is claimed
that compliance with this document may involve the use of a patent.
ISO takes no position concerning the evidence, validity and scope of this patent right.
The holder of this patent right has assured ISO that he/she is willing to negotiate licences under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In
this respect, the statement of the holder of this patent right is registered with ISO. Information may be
obtained from the patent database available at www .iso .org/ patents.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those in the patent database. ISO shall not be held responsible for identifying
any or all such patent rights.
viii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
INTERNATIONAL STANDARD ISO 21806-10:2021(E)
Road vehicles — Media Oriented Systems Transport
(MOST) —
Part 10:
150-Mbit/s coaxial physical layer
1 Scope
This document specifies the 150-Mbit/s coaxial physical layer for MOST (MOST150 cPHY), a
synchronous time-division-multiplexing network.
This document specifies the applicable constraints and defines interfaces and parameters, suitable
for the development of products based on MOST150 cPHY. Such products include coaxial links, coaxial
receivers, coaxial transmitters, electrical to coaxial converters, and coaxial to electrical converters.
This document also establishes basic measurement techniques and actual parameter values for
MOST150 cPHY.
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 21806-1, Road vehicles — Media Oriented Systems Transport (MOST) — Part 1: General information
and definitions
2)
No JEDEC JESD8C.01, Interface Standard for Nominal 3 V/3,3 V Supply Digital Integrated Circuits
3)
TIA/EIA-644-A-2001, Electrical Characteristics of Low Voltage Differential Signaling (LVDS) Interface
Circuits
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21806-1 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
ECC
electrical to coaxial converter
MOST component that converts an electrical signal into a coaxial signal
2) Available at http:// www .jedec .org/ .
3) Available at https:// wwwt .aonline .org/ itandards/ .
© ISO 2021 – All rights reserved 1
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ISO 21806-10:2021(E)
3.2
CEC
coaxial to electrical converter
MOST component that converts a coaxial signal into an electrical signal
4 Symbols and abbreviated terms
4.1 Symbols
--- empty table cell or feature undefined
A attenuation conformance
C
A DC attenuation
DC_loss
J transferred jitter (RMS)
tr
L return loss
RL
N number of bits per frame
BPF
ρ bit rate
BR
ρ network frame rate
Fs
σ standard deviation
T ambient temperature
A
t TimingMaster delay tolerance
MDT
t unit interval
UI
V output high voltage
OH
V output low voltage
OL
4.2 Abbreviated terms
AC alternating current
AFE analogue frontend
BER bit error rate
BR bit rate
Cd[n] condition
CEC coaxial to electrical converter
cPHY coaxial physical layer
CTR coaxial transceiver
DC direct current
DCA DC adaptive
2 © ISO 2021 – All rights reserved
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ISO 21806-10:2021(E)
DDJ data-dependent jitter
DLL data link layer
DSV digital sum value
ECC electrical to coaxial converter
ECU electronic control unit
EMC electromagnetic compatibility
EMI electromagnetic interference
LVDS Low-Voltage Differential Signalling
MNC MOST network controller
N/A not applicable
PCB printed circuit board
PDF probability density function
PHY physical layer
PLL phase locked loop
RL return loss
RMS root mean square
Rx data encoded digital bit stream being received
SP[n] specification point [n]
Tx data encoded digital bit stream being transmitted
5 Conventions
[3]
This document is based on OSI service conventions as specified in ISO/IEC 10731 .
6 Physical layer service interface to OSI data link layer
6.1 Overview
The physical layer (PHY) service interface specifies the abstract interface to the OSI data link layer
[5]
(DLL), see ISO 21806-6 .
6.2 Data type definitions
The data type Enum is defined as an 8-bit enumeration.
6.3 Event indications and action requests
6.3.1 P_EVENT.INDICATE
The PHY shall use P_EVENT.INDICATE to indicate the occurrence of an event to the DLL.
© ISO 2021 – All rights reserved 3
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ISO 21806-10:2021(E)
P_EVENT.INDICATE{
PHY_Event
}
6.3.2 P_ACTION.REQUEST
P_ACTION.REQUEST shall trigger the execution of a request.
P_ACTION.REQUEST {
PHY_Request
}
6.4 Parameters
6.4.1 PHY_Event
Table 1 specifies the PHY_Event parameter, which notifies the DLL about events.
Table 1 — Parameter passed from PHY to DLL
Parameter Data type Description
PHY_Event
Enum { An event that is reported to the DLL.
PHY_Output_Off,
PHY_Network_Activity
}
Table 2 specifies the parameter values for the PHY_Event Enum.
Table 2 — PHY_Event Enum values
Enum value Description
PHY_Output_Off
MNC transmit terminal is switched off.
PHY_Network_Activity
Network activity is detected at the MNC receive terminal.
6.4.2 PHY_Request
Table 3 specifies the PHY_Request parameter, which is passed from DLL to PHY.
Table 3 — Parameter passed from DLL to PHY
Parameter Data type Description
PHY_Request
Enum { A request from the DLL
cmd_Output_Off,
cmd_Output_On,
cmd_Open_Bypass,
}
Table 4 specifies the parameter values for the PHY_Request Enum.
Table 4 — PHY_Request Enum values
Enum value Description
cmd_Output_Off
Switching off the MNC transmit terminal is requested. By default, it is off.
cmd_Output_On
Switching on the MNC transmit terminal is requested. By default, it is off.
4 © ISO 2021 – All rights reserved
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ISO 21806-10:2021(E)
Table 4 (continued)
Enum value Description
cmd_Open_Bypass
Opening the bypass is requested. By default, the bypass is closed.
7 Basic physical layer requirements
7.1 Logic terminology
7.1.1 Single-ended low-voltage digital signals
For the parameters provided in JEDEC No. JESD8C.01, Table 5 defines the corresponding terms for
single-ended signals used in this document. These terms are used to describe the logic states of signals
/RST and STATUS.
Table 5 — Terms for single-ended signals
Term Corresponding JEDEC parameter
Low
V (output low voltage)
OL
Logic 0
High
V (output high voltage)
OH
Logic 1
7.1.2 Differential LVDS signals
TIA/EIA-644-A-2001 uses the labels A and B for the device output terminals; this document uses P and
N, respectively. Table 6 specifies the terms for LVDS signals. The terms correspond to the TIA/EIA-
644-A-2001 specification.
Table 6 — Terms for LVDS signals
Term Corresponding JEDEC parameter
Low
The P terminal shall be negative with respect to the N terminal for a binary 0 state.
Logic 0
High
The P terminal shall be positive with respect to the N terminal for a binary 1 state.
Logic 1
Since some of the MOST devices specified in this document use a tri-state LVDS interface, Table 7
specifies the terms for LVDS bus states.
Table 7 — Terms for LVDS bus states
Term Corresponding TIA/EIA description
Disabled
The P and N terminals are in a high impedance state. If small leakage currents
exist, they might cause an indeterminate voltage on the line/load.
Off
Enabled
Th
...
INTERNATIONAL ISO
STANDARD 21806-10
First edition
Road vehicles — Media Oriented
Systems Transport (MOST) —
Part 10:
150-Mbit/s coaxial physical layer
Véhicules routiers — Système de transport axé sur les médias —
Partie 10: Couche coaxiale physique à 150-Mbit/s
PROOF/ÉPREUVE
Reference number
ISO 21806-10:2021(E)
©
ISO 2021
---------------------- Page: 1 ----------------------
ISO 21806-10:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 21806-10:2021(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
4.1 Symbols . 2
4.2 Abbreviated terms . 2
5 Conventions . 3
6 Physical layer service interface to OSI data link layer . 3
6.1 Overview . 3
6.2 Data type definitions . 3
6.3 Event indications and action requests . 4
6.3.1 P_EVENT.INDICATE . 4
6.3.2 P_ACTION.REQUEST . 4
6.4 Parameters . 4
6.4.1 PHY_Event . 4
6.4.2 PHY_Request . . 4
7 Basic physical layer requirements . 5
7.1 Logic terminology . 5
7.1.1 Single-ended low-voltage digital signals . 5
7.1.2 Differential LVDS signals . 5
7.2 Specification points (SPs) . 6
7.3 Phase variation . 6
7.3.1 General. 6
7.3.2 Wander . 6
7.3.3 Jitter . 7
7.3.4 Clock recovery and reference clock . 7
7.3.5 Link quality . 8
7.3.6 MOST network quality .10
8 MOST150 cPHY requirements .13
8.1 General MOST network parameters .13
8.1.1 MOST network coding .13
8.1.2 Link and interconnect type .14
8.1.3 SP details . . .15
8.1.4 Analogue frontend .16
8.1.5 Integration of coaxial transceiver.17
8.2 Models and measurement methods .19
8.2.1 Golden PLL .19
8.2.2 Jitter filter .20
8.2.3 Retimed bypass mode and stress pattern .21
9 Link specifications .21
9.1 General .21
9.2 SP1 .21
9.3 SP2 .22
9.4 Coaxial link requirements .23
9.4.1 Coaxial interconnect, length and attenuation .23
9.4.2 Characteristic impedance and return loss (L ) .26
RL
9.5 SP3 .30
9.6 SP4 .30
© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii
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ISO 21806-10:2021(E)
10 Power-on and power-off .31
10.1 Frequency reference and power supply .31
10.2 Power supply monitoring circuitry .32
10.3 Coaxial transceiver ECC and CEC .32
10.3.1 General.32
10.3.2 CTR requirements .32
10.3.3 ECC requirements .32
10.3.4 ECC power-on and power-off sequence .35
10.3.5 CEC requirements .35
10.3.6 CEC power-on and power-off sequence.37
11 MOST network requirements .38
11.1 SP4 receiver tolerance .38
11.2 TimingMaster delay tolerance .39
11.3 Environmental requirements and considerations .39
12 Electrical interfaces .39
12.1 LVDS .39
12.2 Bit rate and frequency tolerance .40
13 MOST150 cPHY topologies .40
13.1 Daisy chain topologies .40
13.2 Daisy chain structure .42
13.3 2-port nodes .42
13.4 Port1 delay drift .43
14 Device connectors .46
15 SPs for cable extensions .46
16 Coaxial interconnect attenuation .47
Bibliography .49
iv PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 21806-10:2021(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 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.
A list of all parts in the ISO 21806 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.
© ISO 2021 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
ISO 21806-10:2021(E)
Introduction
The Media Oriented Systems Transport (MOST) communication technology was initially developed at
the end of the 1990s in order to support complex audio applications in cars. The MOST Cooperation was
founded in 1998 with the goal to develop and enable the technology for the automotive industry. Today,
1)
MOST enables the transport of high quality of service (QoS) audio and video together with packet data
and real-time control to support modern automotive multimedia and similar applications. MOST is a
function-oriented communication technology to network a variety of multimedia devices comprising
one or more MOST nodes.
Figure 1 shows a MOST network example.
Figure 1 — MOST network example
The MOST communication technology provides:
— synchronous and isochronous streaming,
— small overhead for administrative communication control,
— a functional and hierarchical system model,
— API standardization through a function block (FBlock) framework,
— free partitioning of functionality to real devices,
— service discovery and notification, and
[2]
— flexibly scalable automotive-ready Ethernet communication according to ISO/IEC/IEEE 8802-3 .
MOST is a synchronous time-division-multiplexing (TDM) network that transports different data types
on separate channels at low latency. MOST supports different bit rates and physical layers. The network
clock is provided with a continuous data signal.
1) MOST® is the registered trademark of Microchip Technology Inc. This information is given for the convenience
of users of this document and does not constitute an endorsement by ISO.
vi PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 21806-10:2021(E)
Within the synchronous base data signal, the content of multiple streaming connections and control
data is transported. For streaming data connections, bandwidth is reserved to avoid interruptions,
collisions, or delays in the transport of the data stream.
MOST specifies mechanisms for sending anisochronous, packet-based data in addition to control data
and streaming data. The transmission of packet-based data is separated from the transmission of
control data and streaming data. None of them interfere with each other.
A MOST network consists of devices that are connected to one common control channel and packet
channel.
In summary, MOST is a network that has mechanisms to transport the various signals and data streams
that occur in multimedia and infotainment systems.
The ISO Standards Maintenance Portal (https:/ standards .iso .org/ iso/ ) provides references to MOST
specifications implemented in today's road vehicles because easy access via hyperlinks to these
specifications is necessary. It references documents that are normative or informative for the MOST
versions 4V0, 3V1, 3V0, and 2V5.
The ISO 21806 series has been established in order to specify requirements and recommendations
for implementing the MOST communication technology into multimedia devices and to provide
conformance test plans for implementing related test tools and test procedures.
To achieve this, the ISO 21806 series is based on the open systems interconnection (OSI) basic reference
[1] [3]
model in accordance with ISO/IEC 7498-1 and ISO/IEC 10731, which structures communication
systems into seven layers as shown in Figure 2. Stream transmission applications use a direct stream
data interface (transparent) to the data link layer.
© ISO 2021 – All rights reserved PROOF/ÉPREUVE vii
---------------------- Page: 7 ----------------------
ISO 21806-10:2021(E)
Figure 2 — The ISO 21806 series reference according to the OSI model
The International Organization for Standardization (ISO) draws attention to the fact that it is claimed
that compliance with this document may involve the use of a patent.
ISO takes no position concerning the evidence, validity and scope of this patent right.
The holder of this patent right has assured ISO that he/she is willing to negotiate licences under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In
this respect, the statement of the holder of this patent right is registered with ISO. Information may be
obtained from the patent database available at www .iso .org/ patents.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those in the patent database. ISO shall not be held responsible for identifying
any or all such patent rights.
viii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
INTERNATIONAL STANDARD ISO 21806-10:2021(E)
Road vehicles — Media Oriented Systems Transport
(MOST) —
Part 10:
150-Mbit/s coaxial physical layer
1 Scope
This document specifies the 150-Mbit/s coaxial physical layer for MOST (MOST150 cPHY), a
synchronous time-division-multiplexing network.
This document specifies the applicable constraints and defines interfaces and parameters, suitable
for the development of products based on MOST150 cPHY. Such products include coaxial links, coaxial
receivers, coaxial transmitters, electrical to coaxial converters, and coaxial to electrical converters.
This document also establishes basic measurement techniques and actual parameter values for
MOST150 cPHY.
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 21806-1, Road vehicles — Media Oriented Systems Transport (MOST) — Part 1: General information
and definitions
2)
No JEDEC JESD8C.01, Interface Standard for Nominal 3 V/3,3 V Supply Digital Integrated Circuits
3)
TIA/EIA-644-A-2001, Electrical Characteristics of Low Voltage Differential Signaling (LVDS) Interface
Circuits
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21806-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
ECC
electrical to coaxial converter
MOST component that converts an electrical signal into a coaxial signal
2) Available at http:// www .jedec .org/ .
3) Available at https:// wwwt .aonline .org/ itandards/ .
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ISO 21806-10:2021(E)
3.2
CEC
coaxial to electrical converter
MOST component that converts a coaxial signal into an electrical signal
4 Symbols and abbreviated terms
4.1 Symbols
--- empty table cell or feature undefined
A attenuation conformance
C
A DC attenuation
DC_loss
J transferred jitter (RMS)
tr
L return loss
RL
N number of bits per frame
BPF
ρ bit rate
BR
ρ network frame rate
Fs
ν transferred jitter, calculated using the root-mean-square method
RMS
σ standard deviation
T ambient temperature
A
t TimingMaster delay tolerance
MDT
t unit interval
UI
V output high voltage
OH
V output low voltage
OL
4.2 Abbreviated terms
AC alternating current
AFE analogue frontend
BER bit error rate
BR bit rate
Cd[n] condition
CEC coaxial to electrical converter
cPHY coaxial physical layer
CTR coaxial transceiver
DC direct current
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ISO 21806-10:2021(E)
DCA DC adaptive
DDJ data-dependant jitter
DLL data link layer
DSV digital sum value
ECC electrical to coaxial converter
ECU electronic control unit
EMC electromagnetic compatibility
EMI electromagnetic interference
LVDS Low-Voltage Differential Signalling
MNC MOST network controller
N/A not applicable
PCB printed circuit board
PDF probability density function
PHY physical layer
PLL phase locked loop
RL return loss
RMS root mean square
Rx data encoded digital bit stream being received
SP[n] specification point [n]
Tx data encoded digital bit stream being transmitted
5 Conventions
[3]
This document is based on OSI service conventions as specified in ISO/IEC 10731 .
6 Physical layer service interface to OSI data link layer
6.1 Overview
The physical layer (PHY) service interface specifies the abstract interface to the OSI data link layer
[5]
(DLL), see ISO 21806-6 .
6.2 Data type definitions
The data type Enum is defined as an 8-bit enumeration.
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ISO 21806-10:2021(E)
6.3 Event indications and action requests
6.3.1 P_EVENT.INDICATE
The PHY shall use P_EVENT.INDICATE to indicate the occurrence of an event to the DLL.
P_EVENT.INDICATE{
PHY_Event
}
6.3.2 P_ACTION.REQUEST
P_ACTION.REQUEST shall trigger the execution of a request.
P_ACTION.REQUEST {
PHY_Request
}
6.4 Parameters
6.4.1 PHY_Event
Table 1 specifies the PHY_Event parameter, which notifies the DLL about events.
Table 1 — Parameter passed from PHY to DLL
Parameter Data type Description
PHY_Event
Enum { An event that is reported to the DLL.
PHY_Output_Off,
PHY_Network_Activity
}
Table 2 specifies the parameter values for the PHY_Event Enum.
Table 2 — PHY_Event Enum values
Enum value Description
PHY_Output_Off
MNC transmit terminal is switched off.
PHY_Network_Activity
Network activity is detected at the MNC receive terminal.
6.4.2 PHY_Request
Table 3 specifies the PHY_Request parameter, which is passed from DLL to PHY.
Table 3 — Parameter passed from DLL to PHY
Parameter Data type Description
PHY_Request
Enum { A request from the DLL
cmd_Output_Off,
cmd_Output_On,
cmd_Open_Bypass,
}
Table 4 specifies the parameter values for the PHY_Request Enum.
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Table 4 — PHY_Request Enum values
Enum value Description
cmd_Output_Off
Switching off the MNC transmit terminal is requested. By default, it is off.
cmd_Output_On
Switching on the MNC transmit terminal is requested. By default, it is off.
cmd_Open_Bypass
Opening the bypass is requested. By default, the bypass is closed.
7 Basic physical layer requirements
7.1 Logic terminology
7.1.1 Single-ended low-voltage digital signals
For the parameters provided in JEDEC No. JESD8C.01, Table 5 defines the corresponding terms for
single-ended signals used in this document. These terms are used to describe the logic states of signals
/RST and STATUS.
Table 5 — Terms for single-ended signals
Term Corresponding JEDEC parameter
Low
V (output low voltage)
OL
Logic 0
High
V (output high voltage)
OH
Logic 1
7.1.2 Differential LVDS signals
TIA/EIA-644-A-2001 uses the labels A and B for the device output terminals; this document uses P and
N, respectively. Table 6 specifies the terms for LVDS signals. The terms correspond to the TIA/EIA-
644-A-2001 specification.
Table 6 — Terms for LVDS signals
Term Corresponding JEDEC parameter
Low
The P terminal shall be negative with respect to the N terminal for a binary 0 state.
Logic 0
High
The P terminal shall be positive with respect to the N terminal for a binary 1 state.
Logic 1
Since some of the MOST devices specified in this document use a tri-state LVDS interface, Table 7
specifies the terms for LVDS bus states.
Table 7 — Terms for LVDS bus states
Term Corresponding TIA/EIA descri
...
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