MIL-STD-1553B, MILITARY STANDARD: AIRCRAFT INTERNAL TIME DIVISION COMMAND/RESPONSE MULTIPLEX DATA BUS (21 SEP 1978)., This standard establishes requirements for digital, command/response, time division multiplexing (Data Bus) techniques on aircraft. It encompasses the data bus line and its interface electronics illustrated on Figure 1, and also defines the concept of operation and information flow on multiplex data bus and the electrical and functional formats to be employed.