Bus System Troubleshooting: Definitions
Bus Line
A bus line is a group signal line that transmits serial data in both directions. It may consist of one wire or two. All control units are connected in parallel in current bus systems, this means that the information sent can be heard by all of the connected units.
Bus Subscriber
Any control module connected to a bus line. e.g. DME, IKE, GM, etc.
Gateway
A Gateway module provides a link between different bus lines to provide a means of sending information from a subscriber of one bus line to the subscriber of another. The Gateway module recognizes from the receiver address whether a message is to be routed through the gateway or not. e.g. IKE, KOMBI.
Master controller
A Master Controller of a bus system provides the operating voltage and wake up signals to the subscriber modules. This task may also be performed by several Standby Masters within a bus system, e.g. GM, LCM.
Serial Data
Serial means one event at a time. In data transmission, the technique of time division is used to separate bits of data sent. The messages sent over a bus are configured serially. Each message consists of:
- Transmitter address.
- Length of data.
- Receiver address.
- Command or Information.
- Detailed description of message (data).
- Summary of transmitted information (check sum).
All of the connected control units will receive the information but only the unit in the address will accept and react to the data.
Topology
In the context of communication networks, Topology describes the configuration or arrangement of a network.