Many new vehicles carry control signals around using databuses. Special interfaces have been developed to allow connection to these buses, making it easy to connect up the aftermarket devices. CAN or Controller Area Network (CANBUS) is a serial bus system designed for controlling devices easily within the car.
Technical information on the CAN-BUS system along with the two optical databus systems is presented too. See the links above or below.
Mercedes-Benz is just one of many vehicle manufacturers who utilise CAN.