Pulse Code Modulation Master Unit


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 is an unflown Pulse Code Modulation Master Unit, part of the Space Shuttle avionics suite. The PCMMU combines signals from a variety of sources, both analog and digital, on the Shuttle, and translates them into a digital form that is a standard way to transmit or receive information.

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: black metal, probably aluminum


3-D: 48.3 × 17.1 × 17.8cm, 12.2kg (19 × 6 3/4 × 7 in., 27lb.)

Country of Origin

United States of America



Inventory Number