The application of multiplexing to civilian and military aircraft electrical systems provides substantial improvements in cost, weight reduction, flexibility, reliability and maintainability over conventional hardwired systems. Relay logic and dedicated wires throughout a typical aircraft are replaced with remote data terminals, a twisted-shielded pair data bus, and a programmable central control unit.
System reliability and maintainability is enhanced by the use of dual redundancy, built-in-test and automatic fault isolation and redundant switchover features. The system operation is stable when subjected to electromagnetic interference and electrical system transients. Current developments include a Data Handling System for SOSTEL II, device technology in solid state power controllers, and remotely resettable circuit breakers.
A review of future aircraft electrical systems indicates that integrating the multiplex data terminals with other elements of the electrical systems will provide even further reductions in aircraft wiring.