Multiplexer/ Demultiplexer


Display Status:

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Collection Item Summary:

This unflown device was probably used to test software for the Space Shuttle Multiplexer/Demultiplexer, which processed communications signals. On the top of this device is a set of "EEPROMS" -- electrically-erasable programmable read-only memory chips. As the software is developed, the contents of these chips could be modified by shining u-v light on them. Once the software is validated, it is stored on Read-only chips that would be installed inside the housing.

NASA transferred this to the Smithsonian in 2016.

Collection Item Long Description:

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


Credit Line

Transferred from the National Aeronautics and Space Administration, Johnson Space Center


  • Case: brushed aluminum.
  • Circuit board: various plastics, with silicon chips mounted on plastic sockets.


3-D: 33 × 28.6 × 17.1cm, 17.7kg (13 × 11 1/4 × 6 3/4 in., 39lb.)

Country of Origin

United States of America



Inventory Number