The original purpose of this document was to establish interface requirements for modular avionics backplanes to be prototyped up to 1995. The document was issued as ARD50011 in September 1992. It is being reissued as an SAE Aerospace Information Report (AIR) in order to: a. preserve the requirements for more than 2 years; b. support design of retrofits and avionics systems to be fielded in the years 1995 to 2000; and c. provide a baseline for updating the requirements of future integrated systems. These requirements were and are intended to promote standardization of modular avionic backplane interfaces. These requirements have been driven predominantly, but not exclusively, by aerospace type military platforms.