Space Shuttle Multiplexer De-Multiplexer (MDM), measuring approximately 10 x 32 x 8, bearing a North American Rockwell Autonetics parts tag reading, “Des. MDM, Ser. No. A009Y, Part No. 11200-507-1, Spec. MC615-0004A, Multiplexer-Demultiplexer, Engineering Model.” An additional testing tag dated 1983 is affixed above. The unit is stenciled “Engineering Test Only” and has a dozen connection ports on the front labeled “J1” through “J12.” In fine condition. MDMs were installed aboard each Space Shuttle orbiter and used to convert and format serial digital flight computer commands into separate parallel discrete, digital, and analog commands for vehicle hardware systems. The MDMs also converted and formatted data from vehicle systems into serial digital data for transmission to the General Purpose Computers. This hardware was essential in reducing the complexity of wiring required between the various data nodes on the Shuttle orbiter. A desirable piece of important Space Shuttle hardware. Oversized.
