Typical multiplex data bus system.
A system architecture enabling integration in both federated and integrated modular avionics. A conventional system comprises either 8 or 16 bidirectional lines capable of carrying information to and from a central processing unit memory or an interface device. There are two types of data-bus systems—electrical bus systems, in which the data are transmitted as electrical pulses by wires, and optical data-bus systems, in which the data are transmitted as light pulses by optical fibers. More famous electrical data buses are the MIL standard 1553B, which are widely used in most military aircraft, and the ARINC 429 and the ARNIC 629, which are used in civil aircraft.