Standardisation of CAN buses

A network has been in place for several years which meets the requirements for application in automobiles. It has the name "CAN bus". CAN is the abbreviation for Controller Area Network, which means that certain operations and functions are controlled over a network within a limited area.
For automobiles this means that control units exchange information using a bus system within the automobile in order to meet certain functions.

In order that all units with CAN connections are compatible with each other, the general technical data and properties of the CAN buses are set in so-called protocols. The ISO (International Standardisation Organisation) has declared this protocol a standard and established it in the ISO Standard 11519. The SAE (Society of Automotive Engineers) has also adopted further standards in view of the special requirements in the area of commercial vehicles.

The following table gives an overview of the most important standards:

If an error arises during the transmission of data through the CAN bus, it can be diagnosed in every vehicle using the so-called "K-line" (ISO 9141). However, in the future this line should be eliminated and the diagnostic unit connected directly to the defective CAN bus. The ISO already has a recommendation for this which has yet to be adopted.