In today's commercial vehicles the electrical and electronic systems are segmented into two different areas, the chassis and the body. The technical interface and achievable level of standardization and integration between these areas is often quite varied and difficult between vehicle manufacturers and component suppliers.
Stand alone electronic modules and subsystems with the ability of processing and controlling a reasonable amount of functions (ECM, EDC, FMC, ABS, TCS…) are state of the art applications on the chassis. They are linked together by controller area networks (CAN-Bus Systems). All these individual modules are quite similar for the various applications and highly standardized (SAE J1939).
However, things have developed quite differently on the body electrical system side, where a multitude of operational functions with drastic differences in complexity are linked together by dedicated wiring. The sheer number of components and interactive operational equipment requires a maze of wiring contained in numerous harnesses, normally meeting at junction blocks or the instrument panel area. This is especially true for metrobuses, coaches, special purpose vehicles with customized bodies like fire-trucks, construction equipment and agricultural vehicles.
To overcome these problems, multiplexing systems have been discussed for some time. The broad application of such systems is still open for standardization. This is where an Onboard Electronic Multiplexing System can reduce the complexity of commercial vehicle central electrical systems.