ISO 22900-1:2008

Road vehicles — Modular vehicle communication interface (MVCI) — Part 1: Hardware design requirements

ISO 22900-1:2008 provides the framework to allow diagnostic and reprogramming software applications from all vehicle manufacturers the flexibility to work with multiple vehicle communication interfaces (VCI) from multiple tool suppliers. This system enables each vehicle manufacturer to support all vehicle communication interfaces to perform diagnostics and to control the programming sequence for electronic control units (ECUs) in their vehicles. ISO 22900-1:2008 describes the applicable use cases to justify the benefits of ISO 22900. It also specifies the design requirements to be followed by diagnostic and programming vehicle communication interface designers. The design requirements are categorized into different levels of conformance classes to provide: “software compliance”, a set of requirements for existing VCIs, which are software but not hardware compliant; “electrical compliance”, defining all signals and electrical interfaces that allow a system integrator to connect more than one VCI Protocol Module to the vehicle diagnostic connector and the host system; “mechanical compliance”, defining standard connectors on the VCI Protocol Module to interface to the vehicle Data Link Connector (DLC) and the host system, as well as defining a cabling concept to support interfacing more than one VCI Protocol Module. The technical requirements specified in ISO 22900-1:2008 have been influenced by the requirements of legal authority with regard to “vehicle OBD and programming”. The Modular Vehicle Communication Interface hardware design requirements will provide appropriate development guidance for vehicle communication interface manufacturers to meet legal authority and automotive manufacturer demands with regard to inter-vendor operability.

Véhicules routiers — Interface de communication modulaire du véhicule (MVCI) — Partie 1: Exigences de conception du matériel

General Information

• Status: Published
• Publication Date: 03-Mar-2008
• ICS: 43.040.15 - Car informatics. On board computer systems
• Technical Committee: ISO/TC 22/SC 31 - Data communication
• Drafting Committee: ISO/TC 22/SC 31/WG 5 - Test equipment/Data eXchange Formats
• Current Stage: 9093 - International Standard confirmed
• Start Date: 02-Jul-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 4869-1:2018 - Acoustics — Hearing protectors — Part 1: Subjective method for the measurement of sound attenuation
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22900-1
First edition
2008-03-15
Road vehicles — Modular vehicle
communication interface (MVCI) —
Part 1:
Hardware design requirements
Véhicules routiers — Interface de communication modulaire du véhicule
(MVCI) —
Partie 1: Exigences de conception du matériel

Reference number
©
ISO 2008
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ii © ISO 2008 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Abbreviated terms . 2
5 Specification release version information . 3
5.1 Specification release version location . 3
5.2 Specification release version . 3
6 Use cases . 3
6.1 OEM merger. 3
6.2 Compatibility between VCIs from after-market tool suppliers. 3
6.3 Future vehicle technology and data link(s). 4
7 Modular VCI concept . 4
7.1 Compliance levels. 4
7.2 Tier 1 Modular VCI software compliance (SC) . 4
7.3 Tier 2 Modular VCI electrical compliance (EC) . 5
7.4 Tier 3 Modular VCI mechanical compliance (MC). 6
7.5 Difference between software (SC) and electrical compliant (EC) MVCI Protocol Modules . 7
8 Modular VCI compliance levels, hardware configurations and design requirements. 8
8.1 General. 8
8.2 Modular VCI “minimum compatibility” requirement matrix . 8
8.3 Software compliance (SC) level design requirements. 9
8.4 Electrical compliance (EC) level design requirements. 12
8.5 Mechanical compliance (MC) level design requirements. 16
8.6 Data Link Connector (DLC) cable and connector. 21
9 Programmable power supply . 26
10 General electrical requirements. 27
11 General environmental durability requirements. 27
Bibliography . 28

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 22900-1 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
ISO 22900 consists of the following parts, under the general title Road vehicles — Modular vehicle
communication interface (MVCI):
⎯ Part 1: Hardware design requirements
⎯ Part 2: Diagnostic protocol data unit application programming interface (D-PDU API)
⎯ Part 3: Diagnostic server application programming interface (D-Server API)
iv © ISO 2008 – All rights reserved

Introduction
The ISO 22900 series of standards is applicable to diagnose and program vehicle electronic control modules
with off-board applications through the vehicle's communication interface.
This part of ISO 22900 has been established in order to define the requirements of cascading multiple
communication interfaces supporting current, future, and legacy standardized and original equipment
manufacturer (OEM) proprietary protocols implemented by different tool manufacturers. Today's situation in
the automotive after-market requires different vehicle communication interfaces for different vehicle OEMs.
Many vehicle communication interfaces are incompatible with regard to their interconnect ability because this
was not a requirement when designed.
The objective of this part of ISO 22900 is to specify the hardware design requirements to support a “plug and
play” type concept of different vehicle communication interfaces from different tool manufacturers. The
hardware design requirements are applicable to different levels of compliance, and they will address the
inter-vendor operability at the vehicle diagnostic connector end as well as the test equipment end, which
executes the applications (Electronic Control Unit diagnostics, programming, etc.).
Implementation of the Modular Vehicle Communication Interface (MVCI) server concept supports overall cost
reduction to the end user because a single diagnostic or programming application will support many vehicle
communication interfaces supporting different protocols.

INTERNATIONAL STANDARD ISO 22900-1:2008(E)

Road vehicles — Modular vehicle communication interface
(MVCI) —
Part 1:
Hardware design requirements
1 Scope
This part of ISO 22900 provides the framework to allow diagnostic and reprogramming software applications
from all vehicle manufacturers the flexibility to work with multiple vehicle communication interfaces (VCI) from
multiple tool suppliers. This system enables each vehicle manufacturer to support all vehicle communication
interfaces to perform diagnostics and to control the programming sequence for electronic control units (ECUs)
in their vehicles.
This part of ISO 22900 describes the applicable use cases to justify the benefits of ISO 22900. It also
specifies the design requirements to be followed by diagnostic and programming vehicle communication
interface designers. The design requirements are categorized into different levels of conformance classes to
provide:
⎯ “software compliance”, a set of requirements for existing VCIs, which are software but not hardware
compliant;
⎯ “electrical compliance”, defining all signals and electrical interfaces that allow a system integrator to
connect more than one VCI Protocol Module to the vehicle diagnostic connector and the host system;
⎯ “mechanical compliance”, defining standard connectors on the VCI Protocol Module to interface to the
vehicle Data Link Connector (DLC) and the host system, as well as defining a cabling concept to support
interfacing more than one VCI Protocol Module.
The technical requirements specified in this part of ISO 22900 have been influenced by the requirements of
legal authority with regard to “vehicle OBD and programming”.
The Modular Vehicle Communication Interface hardware design requirements will provide appropriate
development guidance for vehicle communication interface manufacturers to meet legal authority and
automotive manufacturer demands with regard to inter-vendor operability.
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 15031-3, Road vehicles — Communication between vehicle and external equipment for emissions-related
diagnostics — Part 3: Diagnostic connector and related electrical circuits, specification and use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Universal Serial Bus On-The-Go
USB OTG
supplement to the USB 2.0 specification that augments the capability of mobile devices and USB peripherals
by adding host function for connection to USB peripherals
3.2
Ethernet
physical network media type
4 Abbreviated terms
API Application Programming Interface
ASCII American Standard for Character Information Interchange
DLC Data Link Connector
DLL Dynamic Link Library
D-PDU API Diagnostic Protocol Data Unit Application Programming Interface
D-Server API Diagnostic Server Application Programming Interface
EC Electrical Compliance
ECU Electronic Control Unit
MC Mechanical Compliance
MVCI Modular Vehicle Communication Interface
ODX Open Diagnostic data eXchange
OEM Original Equipment Manufacturer
PC Personal Computer
PDA Personal Digital Assistant
PDU Protocol Data Unit
PEC Protocol Expansion Connector
PEM Protocol Expansion Module
PES Protocol Expansion Slot
SC Software Compliance
USB Universal Serial Bus
USB OTG Universal Serial Bus On-The-Go
2 © ISO 2008 – All rights reserved

5 Specification release version information
5.1 Specification release version location
Specification release version information is contained in each Modular VCI release document specification
under the same title “Specification release version information”. It is important to check for feature support
between Modular VCI release specifications if the hardware and most recent API features shall be
implemented. The D-PDU-API supports the reading of version information by the API function call
PDUGetVersion.
Release version information is also contained in the following files:
⎯ Root Description File (RDF);
⎯ Module Description File (MDF);
⎯ Cable Description File (CDF);
⎯ D-PDU API Library File.
5.2 Specification release version
The specification release version of this part of ISO 22900 is: V2.2.0.
6 Use cases
6.1 OEM merger
In the past, several OEMs in the automotive industry have merged into one company.
All companies leverage existing (legacy) components and jointly develop new products, which are common
across different vehicle types and badges. OEMs specify requirements and design electronic systems to be
implemented in multiple vehicle platforms in order to avoid re-inventing a system for different vehicles. The
majority of design, normal operation, and diagnostic data of an electronic system are re-used if installed in
various vehicles. This may create situations where more than one OEM proprietary vehicle communication
protocol needs to be supported by the off-board diagnostic and programming VCI.
At least two possible solutions are available to address this scenario:
a) each dealership of the newly formed company shall have all OEM proprietary VCIs to diagnose/program
the new vehicle design with carry over components/ECUs from legacy vehicles;
b) each dealership of the newly formed company shall have a Modular VCI which meets the “mechanical
compliance” requirement.
Solution b) is more attractive to an after-market dealership because of the flexibility to enhance the
communication capability at any time.
6.2 Compatibility between VCIs from after-market tool suppliers
The after-market tool suppliers design VCIs according to protocol standards, which are referenced by legal
authorities or implemented by OEMs to diagnose and program vehicle servers. Each VCI behaves differently
and requires individual support and maintenance.
The Modular VCI concept provides different levels of compliance to provide compatibility between different
Modular VCIs from different after-market tool suppliers.
6.3 Future vehicle technology and data link(s)
Vehicle technology is growing into faster and more complex data links. Legal authorities request industry to
agree on a single solution data link, but do not limit the vehicle manufacturer to implement faster data busses,
which might be connected to the vehicle diagnostic connector manufacturer proprietary pins.
Non Modular VCI compliant interfaces meet the communication requirements as specified for a particular
model line, model year range, or a certain number of data links and protocols. In many cases, a VCI needs to
be replaced if a new diagnostic data bus or protocol is implemented in the vehicle.
In order to adapt to new vehicle technology and data links, the Modular VCI concept specifies different
compliance levels, which accommodate various levels of compatibility to provide data link and protocol
enhancement capabilities.
7 Modular VCI concept
7.1 Compliance levels
This clause specifies three different compliance levels for the Modular VCI concept, as described in Table 1.
Table 1 — Modular VCI compliance levels
Tier MVCI compliance levels Description
Software compliance defines a set of requirements for existing VCIs, which are
1 Software compliance (SC)
software but not hardware compliant (e.g. software solution).
Electrical compliance defines all signals and electrical interfaces that allow a
system integrator to connect more than one VCI Protocol Module to the vehicle
2 Electrical compliance (EC)
diagnostic connector and the host system. This compliance level includes Tier 1
Modular VCI software compliance.
Mechanical compliance defines standard connectors on the VCI Protocol
Module to interface with the vehicle DLC and the host system. In addition, it
3 Mechanical compliance (MC) defines a cabling concept to support interfacing more than one VCI Protocol
Module. This compliance level includes Tier 1 Modular VCI software compliance
and Tier 2 Modular VCI electrical compliance.
7.2 Tier 1 Modular VCI software compliance (SC)
This compliance level neither requires compatibility between vehicle communication interfaces nor scan tool.
Compliance is required in software and specified in ISO 22900-2 and ISO 22900-3.
Figure 1 shows software compliant VCI Protocol Module linked to the vehicle diagnostic connector utilizing the
original cable [D] and diagnostic connector adapter [C]. The cable [D] is linked to the diagnostic connector
adapter [C] via the connector [B]. The software compliant VCI Protocol Module uses the connection [J] to the
host system. The host connection can be realized via cable or standard wireless technology.
4 © ISO 2008 – All rights reserved

Key
A MVCI Protocol Module standardized DLC connector
B DLC connector to plug-in diagnostic connector adapter
C Diagnostic connector adapter
D Data Link Cable (DLC)
J MVCI Protocol Module host connector
Figure 1 — Use case of Modular VCI software compliance (SC)
7.3 Tier 2 Modular VCI electrical compliance (EC)
This compliance level requires a high impedance state as the default state (power down, power on and no
communication established) for each communication port (physical layer) supported in the electrical compliant
VCI Protocol Module or scan tool hardware. This is required in order to combine more than one VCI Protocol
module and/or scan tool hardware via a “Y-cable” design to the vehicle diagnostic connector. The
communication ports shall only be enabled by software commands to the VCI Protocol Module or scan tools. It
shall be the responsibility of the diagnostic, programming, and other applications to only enable electrically
compatible protocols as well as valid combinations of communication protocols at the same diagnostic
connector pin.
In addition, compliance is required in software and specified in ISO 22900-2 and ISO 22900-3.
The following describes a use case of more than one MVCI (EC) Protocol Module.
Figure 2 shows two electrical compliant MVCI (EC) Protocol Modules linked to the vehicle diagnostic
connector utilizing the original cable [D] and the diagnostic connector adapter. A “Y” type cable [E] is used to
connect both MVCI (EC) Protocol Modules to the DLC cable [D]. The tool supplier is free to choose the vehicle
DLC connector types. It is recommended, but not required, to use the same DLC connector type as specified
for “mechanical compliance”.
Figure 2 only shows one cable configuration of multiple configurations that are possible. It is the system
integrator’s responsibility to ensure that the cabling system is compatible with the MVCI (EC) Protocol
Modules that are being used.
Each MVCI (EC) Protocol Module uses a different connection [J] to the host system. In this example, the host
connection of MVCI (EC) Protocol Module #1 is cable based and the MVCI (EC) Protocol Module #2 uses a
standard wireless technology [cable of MVCI (EC) Protocol Module #2 is also shown because this is the
standard interface to be implemented].
Key
A MVCI Protocol Module standardized DLC connector
B DLC connector to plug-in diagnostic connector adapter
C Diagnostic connector adapter
D Data Link Cable (DLC)
E “Y” type cable is used to connect both MVCI (EC) Protocol Modules to the DLC cable
J MVCI Protocol Module host connector (either wired or wireless)
Figure 2 — Use case of two electrical compliant MVCI (EC) Protocol Modules
7.4 Tier 3 Modular VCI mechanical compliance (MC)
The mechanical compliance level requires a chassis with at least one vehicle protocol expansion slot to insert
a vehicle Protocol Expansion Module (PEM). The purpose of this compliance level is to support protocol
upgrade capability by a plug-in vehicle Protocol Expansion Module(s) into a Modular VCI chassis. The chassis
provides a tool supplier specific vehicle Protocol Expansion Slot (PES) for a plug-in vehicle Protocol
Expansion Module/card (PEM). In addition, the chassis may provide appropriate space for an integrated or
plug-in server module/card.
The vehicle protocols integrated into a Modular VCI chassis are required to support a high impedance state
for each vehicle protocol port (physical layer). This requirement enables the system to support multiple
protocols on the same pin of the vehicle diagnostic connector. The vehicle communication ports shall be
enabled by software commands. It shall be the responsibility of the diagnostic, programming, and other
applications to only enable electrical compatible vehicle protocols as well as valid combinations of vehicle
communication protocols at the same diagnostic connector pin.
Standard connectors are required on the chassis to interface with the vehicle Data Link Connector (DLC) and
the host system. The vehicle Data Link Connector is specified in 8.6.2. The host system connector is specified
in 8.5.5.5.
In addition, it defines a cabling concept to support interfacing more than one VCI Protocol Module.
Figure 3 shows one possible use case of Modular VCI mechanical compliance.
This Modular VCI chassis [A] has a server board [B], which also includes a base set of vehicle communication
protocols. The front side of the chassis [A] provides two Protocol Expansion Slots (PES) [C] and [D]. A tool
supplier specific vehicle Protocol Expansion Module/card (PEM) [E] can be inserted into the chassis [A].
6 © ISO 2008 – All rights reserved

Key
A Modular VCI chassis
B MVCI server board
C MVCI front side of the chassis
D Protocol Expansion Slots (PES)
E Protocol Expansion Module/card (PEM)
Figure 3 — Use case of Modular VCI mechanical compliance (MC)
7.5 Difference between software (SC) and electrical compliant (EC) MVCI Protocol Modules
The difference between software and electrical compliant MVCI Protocol Modules is the support of high
impedance state as the default state (power down, power on, and no communication established) for each
communication port (physical layer) supported in the vehicle communication interface hardware of the
electrical compliant VCI Protocol Module. Electrical compliant MVCI Protocol Modules can be connected in
parallel to the vehicle diagnostic connector. This is not possible with software compliant MVCI Protocol
Modules.
In addition, the MVCI (EC) Protocol Module shall support, at a minimum, an Ethernet interface or a USB
interface to the host computer system. The USB interface may be the USB 1.1 slave interface or USB OTG
connection scheme. Additional host interfaces (e.g. wireless) can also be implemented.
Both compliance levels require the support of the D-PDU API in software. The host system interface [J] is tool
supplier specific for both compliance levels. The DLC connection [A] is tool supplier specific for the software
compliance level. The electrical compliance level requires an industry standard connector as specified in 8.6.2.
Figure 4 shows Software (SC) and electrical (EC) compliant MVCI Protocol Modules.
Key
A MVCI (SC) Protocol Module tool supplier specific DLC connection
J MVCI (SC) Protocol Module host connection
A MVCI (EC) Protocol Module standardized DLC connection
J MVCI (EC) Protocol Module host connection
Figure 4 — Software (SC) and electrical (EC) compliant MVCI Protocol Modules
8 Modular VCI compliance levels, hardware configurations and design
requirements
8.1 General
The Modular VCI hardware requirements vary according to the three compliance levels described below.
a) The “software compliance level (SC)” does not define any Modular VCI hardware requirements.
Software compliance can be reached by supporting either the D-PDU API as specified in ISO 22900-2, or
the D-Server API as specified in ISO 22900-3.
b) The “electrical compliance level (EC)” specifies Modular VCI hardware requirements in the physical
vehicle communication protocol layer interface. It defines all signals and electrical interfaces that allow a
system integrator to connect more than one VCI Protocol Module. Electrical compliance can be reached
by supporting either the D-PDU API as specified in ISO 22900-2, or the D-Server API as specified in
ISO 22900-3, and in addition, the high impedance state switches for each communication port (physical
layer).
c) The “mechanical compliance level (MC)” specifies standard connectors on the VCI Protocol Module to
interface with the vehicle DLC and the host system. In addition it defines a cabling concept to support
interfacing more than one Modular VCI chassis. This compliance level includes Tier 1 Modular VCI
software compliance and Tier 2 Modular VCI electrical compliance.
8.2 Modular VCI “minimum compatibility” requirement matrix
The “minimum compatibility” requirement matrix (see Table 2) provides an overview about available
alternatives deriving from implementation and design use cases combined with a reference to applicable
Modular VCI specifications.
8 © ISO 2008 – All rights reserved

Table 2 — Modular VCI “minimum compatibility” requirement matrix
Modular VCI supported alternatives and applicable specifications
Required clause of ISO 22900 Required clause of ISO 22901
Modular VCI specification part ODX specification
Part 4: Part 5:
Applicable Modular VCI alternatives
Part 1: Part 2: Part 3: Enhanced Emissions-
Hardware D-PDU D-Server Diagnostic related data
design API API Data in ODX (OBD) in ODX
a
format format
ODX support for OBD data with software
#1 8.3 all clauses — — all clauses
compliant VCI Protocol Module
ODX support for OBD data with electrical
#2 8.4 all clauses — — all clauses
compliant VCI Protocol Module
ODX support for OBD data with
#3 mechanical compliant VCI Protocol 8.5 all clauses — — all clauses
Module
ODX support for Enhanced Diagnostic
#4 Data with software compliant VCI Protocol 8.3 all clauses — all clauses —
Module
ODX support for Enhanced Diagnostic
#5 Data with electrical compliant VCI Protocol 8.4 all clauses — all clauses —
Module
ODX support for Enhanced Diagnostic
#6 Data with VCI mechanical compliant 8.5 all clauses — all clauses —
Protocol Module
#7 Modular VCI software compliance 8.3 all clauses — — —
#8 Modular VCI electrical compliance 8.4 all clauses — — —
#9 Modular VCI mechanical compliance 8.5 all clauses — — —
Modular VCI D-Server API support and
#10 8.3 all clauses all clauses — —
software compliance
Modular VCI D-Server API support and
#11 8.4 all clauses all clauses — —
electrical compliance
Modular VCI D-Server API support and
#12 8.5 all clauses all clauses — —
mechanical compliance
a
Emissions-related diagnostic data in ODX is the subject of a future part of ISO 22901, which is currently under development.
8.3 Software compliance (SC) level design requirements
8.3.1 Applicable Modular VCI hardware configurations according to software compliance (SC)
This subclause specifies the minimum requirements to be fulfilled if the Modular VCI shall meet the “software
compliance (SC)” level.
Figure 5 and Figure 6 explain the various possible Modular VCI configurations in order to reach software
compliance level. Two alternatives are possible for software compliance.
NOTE This figure does not show all possible system partitioning.
Figure 5 — Software compliant (SC) system hardware alternative #1
The application requirements are not covered by this part of ISO 22900. The host custom application supports
the D-PDU API to the MVCI (SC) Protocol Module.
The software compliant MVCI Protocol Module only supports the D-PDU API. It is the tool supplier's
responsibility which vehicle communication protocols are supported.
The Modular VCI tool supplier specific DLC (Data Link Connector) cable is designed to connect one VCI
Protocol Module to the vehicle diagnostic connector.
10 © ISO 2008 – All rights reserved

NOTE This figure does not show all possible system partitioning.
Figure 6 — Software compliant (SC) system hardware alternative #2
The application requirements are not covered by this part of ISO 22900. The software compliant Modular VCI
supports the D-Server API (TCP/IP based protocol).
The software compliant MVCI Protocol Module only supports the D-PDU API. It is the tool supplier's
responsibility which vehicle communication protocols are supported.
The Modular VCI tool supplier specific DLC (Data Link Connector) cable is designed to connect one VCI
Protocol Module to the vehicle diagnostic connector.
8.3.2 MVCI (SC) Protocol Module hardware requirements
8.3.2.1 MVCI (SC) Protocol Module ground isolation
No hardware requirements are specified in this part of ISO 22900 which are applicable to the design of a
software compliant (SC) MVCI Protocol Module.
The MVCI (SC) Protocol Module is not required to support ground isolation between the DLC connector and
the host interface connector end.
8.3.2.2 MVCI (SC) Protocol Module power supply requirements
It is the tool supplier's responsibility, which voltage range, current and tolerances are supported by the power
supply in the design of the MVCI (SC) Protocol Module. These requirements depend on the vehicle protocols
and diagnostic connector specifications to be supported. The amount of current drawn from the vehicle shall
be consistent with the diagnostic connector specification.
8.3.3 MVCI (SC) Protocol Module usage requirements
The MVCI (SC) Protocol Module is required to operate in a “single VCI” environment when connected
between a vehicle and host system.
8.3.4 MVCI (SC) Protocol Module interface requirements
8.3.4.1 MVCI (SC) Protocol Module vehicle communication interface requirements
It is the tool supplier's responsibility which vehicle communication protocols are supported in the design of the
MVCI (SC) Protocol Module.
8.3.4.2 MVCI (SC) Protocol Module host communication interface requirements
It is the tool supplier's responsibility which host interface protocol is supported in the design of the MVCI (SC)
Protocol Module.
8.3.5 MVCI (SC) Protocol Module API support
Software compliance requires applicability to Part 2 of the Modular VCI document that specifies the “D-PDU
(Diagnostic Protocol Data Unit) API” to be supported by the host interface. This API provides a set of function
calls to allow protocol independent message data content transfer between the host system software and the
MVCI (SC) Protocol Module interface.
8.3.6 MVCI (SC) Protocol Module design
There are no design requirements specified in this part of ISO 22900 for the development of a diagnostic
and/or programming interface or scan tool. Any type of housing, material, dimensions and connector types
can be chosen for the design of the software compliant MVCI (SC) Protocol Module. For example, an optional
host interface (e.g. wireless technology by a plug-in PCMCIA card) can be supported instead of an industry
standard (i.e. USB host interface).
8.4 Electrical compliance (EC) level design requirements
8.4.1 Applicable Modular VCI hardware configurations according to electrical compliance (EC)
This subclause specifies the minimum requirements to be fulfilled if the Modular VCI shall meet the “electrical
compliance (EC)” level.
12 © ISO 2008 – All rights reserved

Figure 7 and Figure 8 explain the various possible Modular VCI configurations in order to reach electrical
compliance. Two alternatives are possible for electrical compliance level.

NOTE This figure does not show all possible system partitioning.
Figure 7 — Electrical compliance (EC) system hardware alternative #1
The application requirements are not covered by this part of ISO 22900. The host custom application supports
the D-PDU API and uses at a minimum the USB or Ethernet as a physical interface. The physical interface to
the MVCI Protocol Module is not defined in this part of ISO 22900 (e.g. WIN32 PDU DLL, shared objects, etc.).
The electrical compliant MVCI Protocol Module(s) supports the D-PDU API and uses at a minimum the USB
1.1 slave (or USB OTG) or Ethernet as a physical interface. It is the tool supplier's responsibility which vehicle
communication protocols are supported.
The Modular VCI tool supplier specific DLC (Data Link Connector) cable is designed either with a “Y” or
“splitter” type cable to connect more than one VCI (EC) Protocol Module to the vehicle diagnostic connector.
NOTE This figure does not show all possible system partitioning.
Figure 8 — Electrical compliance (EC) system hardware alternative #2
The application requirements are not covered by this part of ISO 22900. The Modular VCI shown in Figure 8
supports the D-Server API (TCP/IP based protocol).
The Modular VCI Server Module supports the D-Server API and D-PDU API and uses at a minimum the USB
or Ethernet as a physical interface.
The Modular VCI tool supplier specific DLC (Data Link Connector) cable is designed to either support a “Y” or
“splitter” type cable to connect more than one VCI (EC) Protocol Module to the vehicle diagnostic connector.
14 © ISO 2008 – All rights reserved

8.4.2 MVCI (EC) Protocol Module hardware requirements
8.4.2.1 MVCI (EC) Protocol Module ground isolation
No hardware requirements are specified in this part of ISO 22900 which are applicable to the design of an
“electrical compliant (EC)” MVCI Protocol Module except those specified in this subclause.
The MVCI (EC) Protocol Module is required to support ground isolation between the DLC connector and the
host interface connector end.
For an electrically compliant MVCI Protocol Module, ground isolation shall be maintained between the
vehicle’s chassis ground and signal ground (see 8.6.3.2). For a system consisting of multiple MVCI (EC)
Protocol Modules, it is the system integrator’s responsibility to ensure that this ground isolation is maintained.
8.4.2.2 MVCI (EC) Protocol Module power supply requirements
It is the tool supplier's responsibility, which voltage range, current and tolerances are supported by the power
supply in the design of the MVCI (EC) Protocol Module. These requirements depend on the vehicle protocols
and diagnostic connector specifications to be supported.
The requirements below apply.
⎯ The amount of current drawn from the vehicle's diagnostic connector shall be limited to 1 A at 12 V d.c.
(0,5 A at 24 V d.c.) per MVCI (EC) Protocol Module. There shall be no more than three MVCI (EC)
Protocol Modules connected to the vehicle's diagnostic connector at the same time. A “splitter” type DLC
cable shall not have more than three connections to MVCI (EC) Protocol Modules.
⎯ It is the responsibility of the system integrator to ensure compatibility of the power supplies of the MVCI
(EC) Protocol Modules and the vehicle DLC power supply. If one or more MVCI (EC) Protocol Modules
use signal ground for the power return, it is the system integrator’s responsibility to ensure that the
current in the signal ground path complies with the specification for the vehicle’s diagnostic connector (e.g.
no more than 1,5 A for the ISO 15031-3 connector).
8.4.2.3 MVCI (EC) Protocol Module vehicle communication port high impedance requirement
The MVCI (EC) Protocol Module shall include high impedance state switches for each DLC serial
communication data line except power and ground supply lines. This requirement supports the concept of
vehicle communication protocol software selection as needed on a specific pin at the vehicle's diagnostic
connector. The default state of the high impedance state switches at power down, power on and after a reset
shall always be open (no electrical connection). The control of the high impedance state switches shall only be
possible through the API function calls as specified in Part 2 and Part 3 of the Modular VCI specifications.
NOTE When in the high impedance state, the switch may be subject to voltage spikes and other electrical
disturbances, coming from the unused pins, exceeding those specified for the supported protocols. It is the tool supplier’s
responsibility to ensure proper electrical protection of the switch.
8.4.3 MVCI (EC) Protocol Module usage requirements
The MVCI (EC) Protocol Module shall operate in a “single VCI” as well as in a “multiple VCI (maximum of
three (3))” environment when connected between a vehicle and host system.
If more than one MVCI (EC) Protocol Module is required to be connected to the vehicle's diagnostic connector,
a “Y” type or “splitter” type DLC cable (see 8.6.6) is required to route the supported vehicle communication
protocols of more than one MVCI (EC) Protocol Module to the vehicle's diagnostic connector.
8.4.4 MVCI (EC) Protocol Module interface requirements
8.4.4.1 MVCI (EC) Protocol Module vehicle communication interface requirements
It is the tool supplier's responsibility which vehicle communication protocols are supported in the design of the
MVCI (EC) Protocol Module.
8.4.4.2 MVCI (EC) Protocol Module host communication interface requirements
An MVCI (EC) Protocol Module can utilize either USB or Ethernet for host communication. The host
communication interface provides three alternatives to be implemented, as described below.
a) An Ethernet interface: in order to be electrical compliant, an MVCI (EC) Protocol Module shall be able to
communicate at least via 10BaseT with the host system in case of a wired link. An MVCI (EC) Protocol
Module can also use a WLAN interface to be electrical compliant.
b) The USB 1.1 slave interface requires a USB master as a host system in order to perform vehicle
communication. Personal Computers usually have only USB master (host) ports. PDAs and mobile
phones are usually equipped with USB slave ports. To make a Modular MVCI (EC) Protocol Module
“strictly” a USB slave device means that it will only be able to connect to a device capable of being a USB
master (host), precluding the direct use of the vast majority of PDA with USB slave ports as potential
operator interfaces. To implement the full functionality of a USB master (host) port on an MVCI (EC)
Protocol Module would be cost prohibitive, most certainly precluding the concept of integrating both types
of ports on an MVCI (EC) Protocol Module to address this issue.
c) The USB OTG interface provides dual-role (master/slave) functionality and supports master and slave
host systems in order to perform vehicle communication. The USB OTG standard allows for the
implementation of a reduced functionality master (host) port, allowing for a cost effective implementation
on an 8-bit or a 16-bit microcontroller. A USB OTG equipped MVCI (EC) Protocol Module would be able
to connect to either a USB master (host) or a slave with a single USB port, a physical implementation that
only USB OTG provides for. In addition, allowing two OTG ports on an MVCI (EC) Protocol Module would
provide for “integrated HUB” functionality, allowing MVCI (EC) Protocol Modules to be electrically
cascaded in a daisy-chain arrangement.
8.4.5 MVCI (EC) Protocol Module D-PDU API support
Electrical compliance requires applicability to Part 2 of the Modular VCI, which specifies the “D-PDU
(Diagnostic Protocol Data Unit) API” to be supported by the host interface protocol. This API provides a set of
function calls to allow protocol independent message data content transfer between the host system software
and the MVCI (EC) Protocol Module interface.
8.4.6 MVCI (EC) Protocol Module vehicle communication interface connector
There are no design requirements specified in this part of ISO 22900 for the development of the internal
implementation of the diagnostic protocol interfaces and the module housing.
The connector type is tool supplier specific.
The electrical compliance level does not define a certain connector type. This is tool supplier specific. It is
important that all communication related pins have a high impedance switch. This is required in cases where
more than one MVCI (EC) Protocol Module will be connected in parallel.
8.5 Mechanical compliance (MC) level design requirements
8.5.1 Applicable Modular VCI hardware configurations according to mechanical compliance (MC)
This subclause specifies the “minimum” design requirements to be fulfilled if the Modular VCI shall meet the
“mechanical compliance (MC)” level.
16 © ISO 2008 – All rights reserved

Figure 9 and Figure 10 explain the various possible Modular VCI configurations in order to reach mechanical
compliance. Two alternatives are possible for mechanical compliance level.

NOTE This figure does not show all possible system partitioning.
Figure 9 — Mechanical compliant (MC) system hardware alternative #1
The application requirements are not covered by this part of ISO 22900. The host custom application supports
the D-PDU API via USB or Ethernet interface, e.g. WIN32 PDU DLL, shared objects, etc.
The VCI Protocol Module built in the MVCI chassis serves the D-PDU API and uses at a minimum the
USB 1.1 slave (or USB OTG) or Ethernet as a physical interface. The DLC connection provides a power
supply from the vehicle. All MVCI vehicle protocol module enhancements are optional and shall be made
available through the Protocol Expansion Connector (PEC) or through a USB port. Possible enhancement
options are as described below.
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