Modern cars have more electronics than you can think. Almost every vital part has tons of sensors on it with a dedicated computer called ECU (Electrical Control Unit). Usually, there are from several up to hundreds of ECU’s on a single car. Especially luxury ones. All modules have to work as an organized unit. So this is where a reliable connection interface is needed. Probably you’ve already heard of CAN bus (Controller Area Network). It is a standard bus interface used in most vehicles where board computer communicates with separate control ECUs taking care of engine, gearbox, climate, security alarm, safety bags. CAN devices are connected by using twisted pair signal wires that are more resistant to noises. Signals usually operate at the 5V level. The transfer speed can reach up to 1Mb/s for 40m cable lengths.