the vehicle network, as the medium of data exchange. The automotive industry quickly realized the complexity of wiring each module to every other module. Such a wiring design would not only be complex, it would have to be altered depending on which modules were included in the specific vehicle. For example, a car without the anti-lock brake module would have to be wired differently than one that included anti-lock brakes. The industry's answer to this problem was to create a central network in the vehicle. Modules could be 'plugged' into the network and would be able to communicate with any other module that was installed on the network. This design was easier to manufacture, easier to maintain and provided the flexibility to add and remove options without affecting the entire vehicle's wiring architecture. Each module, a node on the vehicle network, controls specific components related to its function and communicates with the other modules as necessary, using a standard protocol, over the vehicle network. Networks were not new, but their application to the vehicle was. The networks for the vehicles called for: Low cost Immunity from external noise Ability to operate in harsh environments Overall robustness and reliability Although the vehicle network made modest demands on data throughput, the demand for more on-board computing is continuing to drive changes to these networks to provide higher-speed communication between modules. The control area network include the receiver and transmitter for the host to controller transmission and interlinking between the computers Protocols, physical media and connectors There are several network types and protocols used in vehicles by various manufactures. Many companies are encouraging a standard communication protocol, but one has not been settled on. Protocols Common vehicle buses protocols include: A²B - (Automotive Audio Bus) An audio distribution protocol developed by Analog Devices AFDX ARINC 429 Byteflight CAN – (Controller Area Network) an inexpensive low-speed serial bus for interconnecting automotive components D2B – (Domestic Digital Bus) a high-speed multimedia interface FlexRay – a general purpose high-speed protocol with safety-critical features IDB-1394 IEBus I²C ISO 9141-1/-2 J1708 and J1587 J1850 J1939 and ISO 11783 – an adaptation of CAN for commercial (J1939) and agricultural (ISO 11783) vehicles Keyword Protocol 2000 (KWP2000) – a protocol for automotive diagnostic devices (runs either on a serial line or over CAN) LIN – (Local Interconnect Network) a very low cost in-vehicle sub-network MOST – (Media Oriented Systems Transport)