WO2003088024A2

WO2003088024A2 - Data conversion device for receiving data from a communication bus of a vehicle

Info

Publication number: WO2003088024A2
Application number: PCT/GB2003/001476
Authority: WO
Inventors: Mike Becker; Adam Denton; Malcolm Norbury; Christopher Roberts; Simon Thorley
Original assignee: Teradyne Diagnostic Solutions Limited
Priority date: 2002-04-04
Filing date: 2003-04-03
Publication date: 2003-10-23
Also published as: WO2003088024A3; AU2003227856A8; GB0207764D0; AU2003227856A1

Abstract

A data conversion device comprising means for receiving data from a communications bus of a vehicle, means for transmitting data to a host system, means configurable to convert the data from a first data format to a second data format, and an interface which is accessible by a user, the interface configured for connection to one or more different modules, the modules being selectable by a user to modify the functionality of the data conversion device.

Description

DATA CONVERSION DEVICE

The present invention relates to a data conversion device.

Modern vehicles incorporate complex electronic and electromechanical active components such as engine management systems, fuel delivery control systems, and brake control systems. Each one of these systems often uses an electronic control unit (ECU). It is conventional to equip vehicles with one or more data communications buses which link the active vehicle components to an appropriate ECU. The individual ECUs may also be connected by a suitable communications bus. There are several standard communications bus types which may be used to link vehicle components together. Application specific variants of these standard bus types are generally used by different vehicle manufacturers. It is also common for vehicles to have multiple buses of different types to meet the requirements of various subsystems

When a vehicle undergoes a routine service, or when an electro-mechanical fault in the vehicle needs to be repaired, a diagnostic system is usually connected to the data communications bus using a suitable connector provided by the communications bus. The connector allows the diagnostic system to obtain data from the ECUs, which allows access to data relating to the operation of the active components. Data can be both real-time, for example engine speed, and/or stored data an example of which might be a "fault-code" which is generated if a specific fault has been detected since the last service.

The diagnostic system may be either a self-contained (integrated) system with a user interface, computing capability and built-in vehicle communications hardware, or a component based system where the user interface and computing capability are features of an application control unit, for example a personal computer, with a connection to the data communications bus of the vehicle via a suitable communications interface unit. Typically, the data formats used by the data communications buses are different for different models of vehicles and for different sub-systems within a single vehicle. The communications interface unit may include a data conversion device aπ-anged to convert the format of data carried by the data communications bus to a format which is compatible with the application control unit. The application control unit is hereinafter referred to as a host.

Different formats of data may be provided on different pins or different combinations of pins of a vehicle's diagnostic connector. Some routing of the data may be required to ensure that data passes to the host on a valid pin or combination of pins. This routing is conventionally provided by a router within the data conversion device, which comprises a series of switches that are arranged to correctly connect certain conductors of the vehicle's diagnostic connector with appropriate conductors within the data conversion device. The router therefore provides flexibility across a diverse set of vehicle types.

A conventional self-contained (integrated) diagnostic system is usually provided with a user interface, computing capability, built-in vehicle communications hardware, and a display. A system of this type is often referred to as a scan tool or tester. The scan tool will typically include software or hardware which converts signals received from the data communications bus to a format suitable for recording in the scan tool, and to a format which may be used to present the data on the display.

Conventional data conversion devices and scan tools suffer from the disadvantage that they provide a user with a very limited amount of flexibility of use. For example, a data conversion device or scan tool may be capable of receiving and reformatting data from a particular manufacturer's range of vehicle models, but will often not be able to receive and reformat data from a different manufacturer's range of vehicle models. A different data conversion device or scan tool specific to that range of models would potentially be required. This is a significant disadvantage as the cost of each data conversion device or scan tool is substantial. A further disadvantage of conventional gateway devices and scan tools is that they may become obsolete when an existing range of vehicle models is replaced with a new range of vehicle models which uses a different format of data communications bus. Furthermore, advances in technology can be accommodated only by the purchase of a new data conversion device.

It is an object of the present invention to provide a data conversion device which overcomes at least one of the above disadvantages.

According to a first aspect of the present invention, there is provided a data conversion device comprising means for receiving data from a communications bus of a vehicle, means for transmitting data to a host system, means configurable to convert the data from a first data format to a second data format, and an interface which is accessible by a user, the interface configured for connection to one or more different modules, the modules being selectable by a user to modify the functionality of the data conversion device.

The interface is preferably a standard interface of the type known as a Personal Computer Memory Card International Association (PCMCIA). The device may be provided with a single PCMCIA interface.

The means configurable to covert the data from a first data format to a second data format preferably comprises a programmable microprocessor. The microprocessor may execute program code stored in a memory within the data conversion device, to perform the data conversion.

The data conversion device may further comprise a non-volatile storage device suitable for storing program code. The data conversion device may further comprise a volatile storage device suitable for transiently storing program code during execution.

The device may be substantially enclosed in a housing, and may be provided with access means. The access means may comprise a panel which is formed from a substance which is substantially transparent to radio frequency electromagnetic waves. The access means may be secured in a closed configuration by user operated locking means which may comprise one or more latches. The data conversion device may further comprising one or more protocol controller integrated circuits suitable for controlling communications between the data conversion device and a vehicle. The device may further include a router which routes signals from certain conductors of the vehicle communications bus to appropriate conductors within the data conversion device. The router may comprise solid state switches, analogue switches or relays.

The module may be a radio frequency communications module and/or a memory module. The module may be a non-volatile memory module for example a FLASH disk, or alternatively a volatile memory module. The module may be configured to control communications between a vehicle and the data conversion device. The module may be configured to control communication between a host and the data conversion device. The module may be provided with a connector suitable for connection to a suitable cable. The module may be a PCMCIA expansion card.

The present invention also provides a PCMCIA expansion card suitable for use with a data conversion device wherein the expansion card is configured to control data transfer between a data conversion device and a vehicle.

According to a second aspect of the present invention, there is provided a data conversion device comprising means for receiving data from a communications bus of a vehicle, means for transmitting data to a host system, and means for converting data received from the vehicle into a foπnat suitable for transmitting to the host system, wherein data is received from the vehicle in a plurality of formats, and the data conversion device is configured to convert said plurality of formats into one or more formats suitable for transmission to the host system.

The data conversion device may configured to convert said plurality of formats into a single format for transmission to the host system. The data conversion device is configurable such that a diagnostic test may be carried out using a plurality of different vehicle formats concurrently, without reconfiguring the data conversion device. For example, a single diagnostic operation may require data to be obtained from different ECUs using different vehicle formats. Data in these different formats is received and processed by the means for converting data, such that data is communicated to the host system in a single suitable format.

It will be appreciated that the features set out above in relation to a data conversion device in accordance with the first aspect of the present invention are equally applicable to a data conversion device in accordance with the second aspect of the present invention.

The present invention further provides a PCMCIA expansion card suitable for use with a data conversion device wherein the expansion card is configured to control data transfer between a data conversion device and a host system.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a schematic illustration of a conversion device according to the present invention in communication with a vehicle and a host system;

Figure 2 is a schematic illustration of the conversion device of figure 1, shown in further detail; and

Figures 3 and 4 are schematic illustrations of alternative methods of communication between a microprocessor and a protocol controller in the data conversion device of figure 2.

Referring to figure 1 a vehicle 1 communicates with a host system 2 via a data conversion device 3. The vehicle comprises a number of electronic control units (ECUs) 4 which are connected together by a number of conductors 5 which form a communications bus. The vehicle 1 also comprises a connector 6 to which a cable can be connected for data transmission to the conversion device 3. In many applications the connector 6 will be an industry standard J1962 connector, a D-type connector which is widely used in such applications. It can be seen from figure 1 that the ECUs 4 denoted A, B, and C are directly connected to the connector 6. Two further ECUs 4 which are denoted D and E do not have a direct connection to the connector 6, but instead have a connection to a gateway device 7 situated within the vehicle. This gateway device in turn communicates with the connector 6. The gateway device 7 provides means to control direct access to the ECUs 4 denoted D and E. This is particularly desirable for ECUs controlling safety critical systems (such as a braking system), where a vehicle manufacturer may wish to carefully limit the access that a diagnostic device has to the ECU.

The data conversion device 3 connects to the connector 6 of the vehicle 1 by means of a cable 8. The cable will comprise a number of conductors and will have plugs fitted at its ends for connection to the vehicle 1 and the data conversion device 3. Similarly, the host system 2 is connected to the data conversion device 3 by means of a suitable cable 9. In use, data requests are transmitted by the host system 2 and received by the data conversion device 3. These requests are processed and passed to an appropriate ECU of the vehicle in an appropriate data format. Data is then transmitted from the vehicle, received by the data conversion device and transmitted to the host system. It will be appreciated that the format of the messages will differ not only between the host system 2 and the vehicle 1, but also between different ECUs 4 within the vehicle 1. The data conversion device 3 is configured so as to handle each of these different data formats.

The data conversion device 3 is illustrated in further detail in figure 2. The device is ideally provided in a durable magnesium die cast enclosure to protect it from damage. The device 3 comprises a microprocessor 10, which may be any one of a number of suitable processors which are readily available. Depending on the exact nature of the device, the processor may operate on word lengths of 8, 16 or 32 bits. Data transmission to and from the vehicle is carried out through a connector 1 1, which is positioned so as to be accessible from the outside of the enclosure.

The connector 11 is suitable for mating with a connector provided by the cable 8. The pins of the connector 11 are connected to a router 12 which is in turn connected to a number of semiconductor vehicle protocol controllers 13. Each vehicle protocol controller 13 is programmed so as to be able to bidirectionally translate data between the microprocessor 10 and a communications bus in the vehicle operating using a predetermined protocol. For example, the data conversion device may be programmed to handle communications using a number of widely used protocols such J1850VPW, J1850PWM, ISO9141, CAN (Controller Area Network), SCI, KWP2000 or other proprietary protocols. Each of the protocols which can be handled by the data conversion device has a corresponding vehicle protocol controller 13.

Industry standards relating to the J1962 connector dictate that particular pins within the connector will communicate with particular systems within the vehicle, and will use particular protocols. Thus it is possible to connect some pins of the connector 11 directly to a suitable vehicle protocol controller 13 as it is known that data received on that pin will always conform to a predetermined protocol. However, the J1962 standard is such that some pins of the connector can carry different data, formatted according to different protocols depending upon the vehicle to which the data conversion device is connected. Thus, a particular pin of the connector 11 may need to be connected to a different vehicle protocol controller 13, depending upon the vehicle to which the device is connected.

The router 12 provides a programmable cross-switch which can connect various pins of the connector 11 to various vehicle protocol controllers 13. The programming of the cross-switch is carried out by the host system (2 in figure 1 ) which is connected to the data conversion device 3.

The microprocessor 10 is also connected to a plurality of host protocol controllers 14. These host protocol controllers 14 allow the device to be connected to a number of different host systems, such as personal computers or portable digital assistants (PDAs). The host protocol controllers 14 support a number of standard communications formats such as Ethernet, USB and RS232. The host protocol controller chips 14 allow a given data conversion device to be used with a variety of different hosts. Each of the host protocol controllers 14 will be capable of handling data formatted according to appropriate industry standard protocols. For example, an Ethernet controller chip may be capable of handling data formatted using the TCP/IP protocols which are widely used in PC network applications. Controller chips for USB and RS232 will similarly use widely applicable serial transmission protocols. The host protocol controllers 14 are each connected to a connector 15 which is suitable for connection to the cable 9.

From the preceding discussion, it will be appreciated that the vehicle protocol controllers 13 form a vehicle interface which allows bi-directional communication between the microprocessor 10 and the vehicle connector 11. Similarly, the host controllers 14 form a host interface which allows bi-directional communication between the host connector 15 and the microprocessor 10. In preferred embodiments of the present invention the microprocessor 10 is able to transmit and receive data using a plurality of vehicle protocol controllers 13 and a plurality of host controllers 14 during a given diagnostic operation. By allowing the microprocessor to access the vehicle protocol controllers and the host controllers in this way, greater flexibility is provided, allowing a number of formats to be handled in a single diagnostic operation.

Referring to figure 3, a first means of communication between a vehicle protocol controller 13 and the microprocessor 10 is illustrated. Both the microprocessor 10 and the vehicle protocol controller 13 are connected to an n bit address bus 16 and an m bit data bus 17. The values of n and m are determined by the word lengths used by the microprocessor for address and data computation. When data is to be transferred from the microprocessor to the vehicle protocol controller 13, the data passes along the data bus 17 in the form of an m bit word. The vehicle protocol controller 13 is then able to receive the words, and decode the information earned therein.

Figure 4 shows an alternative means of communication between a vehicle protocol controller 13 and the microprocessor 10. Here a single bit data line 18 capable of transmitting a stream of bits in series is provided. The data line is configured so as to allow bi-directional data transfer. There is also provided a chip select line 19 to indicate an address to which data is to be written either in the vehicle protocol controller 13 or in the microprocessor and also a single bit read/write line 20, which is configured such that transmission of a ' 1 ' bit on the read/write line indicates that data is to be written, while transmission of a '0' bit indicates that data is to be read. It will be appreciated that in some embodiments, a ' 1 ' bit may indicate a read, while a '0' bit may indicate a write.

Referring back to figure 2, it can be seen that the data conversion device also comprises a volatile memory device 21, which can conveniently be provided in the form of SDRAM, and a non-volatile read-write memory device 22 which can conveniently be provided in the form of FLASH memory.

Figure 2 also shows that in accordance with the present invention, the microprocessor 10 is connected to an expansion card interface 23 which is adapted to receive suitable expansion cards 24. In a preferred embodiment of the invention, the expansion card interface is a Personal Computer Memory Card International Association (PCMCIA) interface which can accept industry standard PCMCIA cards. The provision of an expansion card interface is highly beneficial in allowing the functionality of the data conversion device to be increased after its initial manufacture. A portion of the data conversion device is provided with a removable cover to allow access to the expansion card interface. The removable cover is secured to the enclosure housing the device using latches which are provided on the enclosure (any suitable form of locking means may be used). The removable cover is fabricated from a robust injection moulded plastic material which allows radio frequency signals to propagate unimpeded out of the device and to a receiver.

A wide variety of PCMCIA cards may be used in conjunction with the data conversion device. These include network cards to enhance the connectivity of the device with a host. Suitable network cards include radio frequency local area network communications cards (for example IEEE802.1 1b or Bluetooth™), radio frequency wide area network communications cards (for example cellular GSM or GPRS), or an alternative cabled host interface card (for example USB2 or IEEE1394 Firewire). Altematively, the PCMCIA card may provide further storage capacity in the form of volatile RAM or non-volative FLASH or hard disk drive based memory.

There are several advantages which stem from the flexibility provided by the expansion card interface. A data conversion device may initially be purchased by a user with a cable to connect to a diagnostic host system 2. The user may subsequently want to replace the cable connection with a RF-LAN connection, and this may be done by purchasing a suitable RF-LAN expansion card and fitting it to the expansion card interface. The RF-LAN expansion card will include circuitry to allow data to be bi-directionally communicated with the host system 2 using a suitable RF protocol.

Alternatively, a user may have purchased a data conversion device which is already provided with an integral RF-LAN connection, but may want to be able to transmit data from the device over a long distance. This may be done by purchasing a RF-WAN expansion card and fitting the expansion card to the device. The RF-WAN expansion card will include circuitry to allow transmission of data using an RF-WAN transmission protocol. Data will be passed from the device to the diagnostic host system 2 via the RF-WAN card. The user may drive the vehicle over a considerable distance, for example to test the fuel efficiency and performance of the vehicle's engine, and data may be transmitted from the RF-WAN card whilst the vehicle is being driven.

Other currently available expansion cards may be fitted to the interface to provide other functionality as required by the user.

In addition to conventional expansion cards which are currently available, modules specifically developed for the data conversion device may be used. For example, a module may provide further protocol controllers which can be added to those incorporated within the device.

The data conversion device may be provided with more than one expansion card interface to allow more than one expansion card or module to be fitted to the device simultaneously (for example an RF-LAN and a vehicle protocol controller expansion card).

Operation of the device illustrated in the accompanying figures will now be described. A vehicle is taken to a service bay, and a fault is to be diagnosed. The vehicle has a male J1962 connector 6 of type described above, and a connector provided by the cable 8 is connected to the connector 6. A connector provided on the remote end of the cable 8 is connected to the connector 11 of the data conversion device. Similarly, the cable 9 is com ected between the connector 15 provided by the data conversion device and a suitable connector on the host system 2. In the description that follows, the host system 2 is assumed to be a personal computer, and suitable host connectors may include an RS232 serial port, a USB port or an Ethernet port.

The data conversion device is powered up, and initialisation code stored in the non-volatile memory 22 is executed automatically by the microprocessor 2. This initialisation code initialises the vehicle protocol controllers 13, and configures all other components within the data conversion device to a default configuration. An operator of the system then uses the host system 2 to specify details of the vehicle. This may be done by selecting items from menus provided by software running on the host system 2, or alternatively by entering a vehicle identification number (NLN), which can be looked up in a local or remote database. Either of these methods will determine various model specific parameters, such as the number and configuration of ECUs provided by the vehicle, and the protocols used by these ECUs. The model specific parameters will also include data specifying which protocol is used on each pin of the connector 11 of the data conversion device. This data is used to configure the router 12 such that appropriate pins of the connector 11 are connected to the appropriate vehicle protocol controller 13. The data used to configure the router 12 is carried directly from the host connector 15 to the router 12 via connection 25. The host system 2 will also send a message to the data conversion device in a generic format to indicate which host protocol is to be used for communication between the data conversion device and the host system 2.

Once the basic configuration parameters have been downloaded from the host system 2 to the data conversion device, the user can use the host system 2 to specify diagnostic tasks that are to be undertaken. This can be conveniently achieved using software operating on the host system 2. When the user has chosen a diagnostic task, program code is downloaded from the host system 2 to the data conversion device for storage in the non-volatile storage device 22. This program code is executed by the microprocessor 10 and results in communication being established between the microprocessor 10 and the vehicle via the vehicle protocol controllers 13 and the router 12.

For a given diagnostic task, data requests which relate to the task are sent from the microprocessor 10 to the vehicle. In response to the data requests, an ECU of the vehicle transmits data onto the vehicle's communications bus, and the data passes via the router 12 and vehicle protocol controllers 13 to the microprocessor 10. The program code being executed by the microprocessor 10 formats the received data for transmission to the host system 2 via the host protocol controllers 14.

Some data transmitted from vehicle ECU'S will be in response to specific . . requests from the program code executing on the microprocessor. Some data will be broadcast data which is sent out from an ECU within the vehicle, and received by the data conversion device. For example, a temperature reading may be broadcast from the engine management ECU at periodic predetermined time intervals. Each data packet transmitted by the vehicle is processed by program code executing on the microprocessor 10. The program code examines the contents of each data packet and determines whether the data within that packet should be forwarded to the host system 2. For example whilst some data may be formatted by the microprocessor 10 for , onward transmission to the host system 2 via a host protocol controller 14, other data may be discarded. The vehicle protocol controllers 13 define two interfaces. A first interface is used for communication with the microprocessor, and a second interface is used for communication with the vehicle. Referring back to figure 3, the first interface is made up of the address bus 16 and the data bus 17 which are described above. The second interface (not shown) comprises means for transferring data to and from the vehicle via the router 12 of figure 2. Typically, some data transformation will be required between two interfaces provided by a vehicle protocol controller 13, and the vehicle protocol controller 13 typically handles this. The interfaces are well defined and specify data formats which should be used by program code executing on the microprocessor which is to transmit data to the vehicle, and also allow the vehicle protocol controllers 13 to handle incoming data from the vehicle. The vehicle protocol controllers 13 typically deal with lower level transmission between the vehicle and the data conversion device. The vehicle protocol controllers 13 will typically contain functionality to ensure that data is correctly sequenced and functionality to perform check sum calculations.

The host protocol controllers 14 similarly define two interfaces, one for communication with the microprocessor 10, and one for communication with the host system. Typically, the microprocessor interface provided by the vehicle protocol controllers 13 differs from that provided by the host protocol controllers 14, and the program code executing on the microprocessor 10 will transform data to conform to these interfaces.

The expansion card interface 23 communicates with the microprocessor 10 using conventional interfaces which will be well known to those skilled in the art of computer engineering, for example as detailed in the PCMCIA specification. Thus, the microprocessor can write data to and read data from an expansion card 24 inserted into the interface 23. Conventional protocols are used to determine the nature of the card fitted, and the program code executed by the microprocessor makes use of the card. For example, if the expansion card is an alternative vehicle protocol controller, a cable is connected from a suitable comiector provided by the expansion card to the vehicle (thus bypassing the vehicle protocol controllers 13, the router 12 and the connector 11 of figure 2) and the program code is configured to handle data received from the expansion card interface. Similarly, the program code is also configured to dispatch messages received from the host system 2 to the expansion card interface for onward transmission to the vehicle.

Similarly, the expansion card may be an alternative host protocol controller. For example, the host protocol controller may be a RF-WAN connector. In this case, data is communicated between the microprocessor 10 and the host system 2 via the expansion card, and not via the host protocol controllers 14 and the host connector 15.

If the expansion card provides further storage capacity in the form of nonvolatile storage, program code configured to use this memory may store data on the expansion card so as to increase the storage capacity of the data conversion device. Furthermore, the expansion card may be removed from one data conversion device and stored in another so as to enable data transfer between devices. Such data transfer functionality may be used to allow diagnostic data or program code data to be transferred between conversion devices.

It will be appreciated that the data conversion device may be operated so as to communicate with a variety of vehicle formats and a variety of host formats simultaneously. However, the data conversion device will often use only one host format at a given time. For example, the program code is typically configured so as to communicate in a range of vehicle formats, each via a different vehicle protocol controller, and convert these formats into a single host format for communication with a host system via a host protocol controller

In the embodiment described above, the identity of the vehicle to which the data conversion device is connected is specified by a user using an interface of the host system 2. In an alternative embodiment of the present invention, program code stored in the non-volatile storage device 22 of the microprocessor 10 is executed when the data conversion device is initialised, and this code endeavours to determine the vehicle to which the device is connected. In a preferred embodiment of the present invention, the program code may initially send messages to various ECUs of the vehicle using protocols which are always used on specific pins of the vehicle J1962 connector. For example, a predetermined pin may be set to communicate with an engine management ECU using the CAN protocol in all vehicles. The data conversion device can then send a message in CAN format to the engine management ECU, and use this response to at least partially identify the vehicle. A fuller identification can then be performed by attempting communication with various ECUs which it is known are present on some vehicles, and using the presence or absence of these ECUs as a basis for a fuller identification. Furthermore, some vehicles provide functionality such that an ECU may be queried in such a way as to return data which provides an identification of the vehicle. The identification process described above is stepwise, with additional information being used to more accurately identify the vehicle at each stage. Once a vehicle has been identified in this way the diagnostic process may continue as previously described.

In the embodiment described above, program code to allow communication between the vehicle and the host system is downloaded to the data conversion device from the host system at the time at which a diagnostic operation is to be performed. In an alternative embodiment of the present invention, the data conversion device is used in combination with a dumb terminal which does not have the capacity to download program code to the data conversion device. In such an embodiment, program code is stored on the non-volatile storage device 22, to enable the device to perform some data transformations without requiring program code to be downloaded. The initially stored code may, for example, allow transformation between a predetermined set of host protocols and a predetermined set of vehicle protocols, with further program code being downloaded from a remote device such as an active host system if transformation between other protocols is required. A dumb terminal operating in this way can simply receive data sent by the data conversion device, and report such data to the user.

Claims

1. A data conversion device comprising means for receiving data from a communications bus of a vehicle, means for transmitting data to a host system, means configurable to convert the data from a first data foπnat to a second data format, and an interface which is accessible by a user, the interface configured for connection to one or more different modules, the modules being selectable by a user to modify the functionality of the data conversion device.

2. A data conversion device according to claim 1, wherein the interface is a standard interface of the type known as a Personal Computer Memory Card International Association (PCMCIA).

3. A data conversion device according to claim 1 or 2, wherein the means configurable to convert the data from a first data format to a second data format comprises a programmable microprocessor.

4. A data conversion device according to claim 3, wherein the microprocessor executes program code stored in a memory within the data conversion device, to perfoπn the data conversion.

5. A data conversion device according to any preceding claim, wherein the data conversion device further comprises a non-volatile storage device suitable for storing program code.

6. A data conversion device according to any preceding claim, wherein the data conversion device further comprises a volatile storage device suitable for transiently storing program code or data during execution.

7. A data conversion device according to any preceding claim, wherein the device is substantially enclosed in a housing, and is provided with access means.

8. A data conversion device according to claim 7, wherein the access means comprises a panel, the panel being formed from a substance which is substantially transparent to radio frequency electromagnetic waves.

9. A data conversion device according to claim 7 or 8, wherein the access means may be secured in a closed configuration by user operated locking means.

10. A data conversion device according to claim 9, wherein the locking means comprises one or more latches.

11. A data conversion device according to any preceding claim, further comprising one or more protocol controller integrated circuits suitable for controlling communications between the data conversion device and a vehicle.

12. A data conversion device according to any preceding claim, wherein the device further includes a router which routes signals from certain conductors of the vehicle communications bus to appropriate conductors within the data conversion device.

13. A data conversion device according to claim 12, wherein the router comprises solid state switches, analogue switches or relays.

14. A data conversion device according to any preceding claim, wherein the module is a radio frequency communications module.

15. A data conversion device according to any preceding claim, wherein the module is a memory module.

16. A data conversion device according to claim 15, wherein the module is a nonvolatile memory module.

17. A data conversion device according to claim 15, wherein the module is a volatile memory module.

18. A data conversion device according to any preceding claim, wherein the module is configured to control communications between a vehicle and the data conversion device.

19. A data conversion device according to any preceding claim, wherein the module is configured to control communication between a host and the data conversion device.

20. A data conversion device according to claim 18 or 19, wherein the module is provided with a connector which is accessible when the module is in use, the connector being suitable for connection to a suitable cable.

21. A data conversion device according to any preceding claim, wherein the module is a PCMCIA expansion card.

22. A PCMCIA expansion card suitable for use with a data conversion device wherein the expansion card is configured to control data transfer between a data conversion device and a vehicle.

23. A PCMCIA expansion card suitable for use with a data conversion device wherein the expansion card is configured to control data transfer between a data conversion device and a host system.

24. A data conversion device substantially as hereinbefore described with reference to the accompanying drawings.

25. A data conversion device comprising means for receiving data from a communications bus of a vehicle, means for transmitting data to a host system, and means for converting data received from the vehicle into a format suitable for transmitting to the host system, wherein data is received from the vehicle in a plurality of formats, and the data conversion device is configured to convert said plurality of formats into one or more formats suitable for transmission to the host system.

26. A data conversion device according to claim 25, wherein the data conversion device is configured to convert said plurality of formats into a single format for transmission to the host system.

27. A data conversion device according to claim 25 or 26, further comprising an interface which is accessible by a user, the interface configured for connection to one or more different modules, the modules being selectable by a user to modify the functionality of the data conversion device.

28. A data conversion device according to claim 27, wherein the interface . is a standard interface of the type known as a Personal Computer Memory Card International Association (PCMCIA).

29. A data conversion device according to any one of claims 25 to 28, wherein the means configurable to convert the data from a first data format to a second data format comprises a programmable microprocessor.

30. A data conversion device according to claim 29, wherein the microprocessor executes program code stored in a memory within the data conversion device, to perform the data conversion.

31. A data conversion device according to any one of claims 25 to 30, wherein the data conversion device further comprises a non-volatile storage device suitable for storing program code.

32. A data conversion device according to any one of claims 25 to 31, wherein the data conversion device further comprises a volatile storage device suitable for transiently storing program code or data during execution.

33. A data conversion device according to any one of claims 25 to 32, wherein the device is substantially enclosed in a housing, and is provided with access means.

34. A data conversion device according to claim 33, wherein the access means comprises a panel, the panel being formed from a substance which is substantially transparent to radio frequency electromagnetic waves.

35. A data conversion device according to claim 33 or 34, wherein the access means may be secured in a closed configuration by user operated locking means.

36. A data conversion device according to claim 35, wherein the locking means comprises one or more latches.

37. A data conversion device according to any of claims 25 to 36, further comprising one or more protocol controller integrated circuits suitable for controlling communications between the data conversion device and a vehicle.

38. A data conversion device according to any one of claims 25 to 37, wherein the device further includes a router which routes signals from certain conductors of the vehicle communications bus to appropriate conductors within the data conversion device.

39. A data conversion device according to claim 38, wherein the router comprises solid state switches, analogue switches or relays.

40. A data conversion device according to to claim 27, or any one of claims 28 to 39 as dependent upon claim 27, wherein the module is a radio frequency communications module.

41. A data conversion device according to claim 27, or any one of claims 28 to 40 as dependent upon claim 27, wherein the module is a memory module.

42. A data conversion device according to claim 41, wherein the module is a nonvolatile memory module.

43. A data conversion device according to claim 41, wherein the module is a volatile memory module.

44. A data conversion device according to claim 27, or any one of claims 28 to 43 as dependent upon claim 27, wherein the module is configured to control communications between a vehicle and the data conversion device.

45. A data conversion device according to any to claim 27, or any one of claims 28 to 43 as dependent upon claim 27, wherein the module is configured to control communication between a host and the data conversion device.

46. A data conversion device according to claim 44 or 45, wherein the module is provided with a connector which is accessible when the module is in use, the connector being suitable for connection to a suitable cable.

47. A data conversion device according to claim 27, or any one of claims 28 to 46 as dependent upon claim 27, wherein the module is a PCMCIA expansion card.