CANB101
What is a CANBus, and why is it used?_
Developed in the 1980's by Bosch, Published in 1991 as CAN2.0,The Controller Area Network is a multi-master serial communication network of modules(ECUs) connected by a twisted pair of wires - **CAN-High **and CAN-Low. Messages are broadcast by nodes on the network, and each node receives every message. Critical and important messages are prioritised via an Arbitration Identifier which makes up part of the CAN-Data Frame. CAN become an International Standard in 1993, as ISO 11898. CAN-Flexible-Data (FD) 1.0 was released by Bosch in 2012. Development continues to this day as new technologies and internet connectivity play an increasingly larger part in modern vehicles.
The twisted pair of wires that transmit CAN messages operate at a voltage relative to one another, meaning that any electromagnetic interference _(eg wiring harness in proximity to alternator)_experienced by one wire will be experienced by the other, and the while voltage may be effected by such interference - the difference between CAN-High + CAN-Low remains the same and messages are still recieved on the bus. In an idle state both CAN wires sit at approximately 2.5 Volts
