Society of Automotive Engineers AS4074 family high-speed, fault-tolerant data communications standards for integrated avionics

The Society of Automotive Engineers (SAE) has been addressing the need for data buses in advanced avionics systems. Since 1979, the SAE has had task groups developing a family of commercial data bus standards designed specifically for the unique fault-tolerant requirements of avionics applications: AS4074.1 linear, token-passing multiplex data bus (LTPB) and AS4074.2 high-speed ring bus (HSRB). The author explains the background of the two bus standards, gives a brief overview of the two protocols, and reviews current and future SAE activities in the avionics data bus field. It is concluded that the SAE LTPB and HSRB satisfy the data latency needs of emerging avionics architectures, as well as the reliability and fault tolerance requirements. Because of their ability to be supplemented with higher data rate versions, they will continue to support emerging avionics architectures