140 Mbit/s Coder/Decoder Rack, Ground Equipment, Communications Satellite

As engineers developed communications satellites in the 1960s and after, they faced a key problem: For any signal to or from a satellite, how do you pack in as much information as possible, with minimal loss or error. One part of an answer was the development of modems (devices for connecting analog communication sources with digital computers and vice versa).

This device, the coded octal phase shift keying (COPSK) modem, was developed in the mid 1980s by COMSAT Laboratories to improve the performance of Intelsat communications satellites. In use, the modem was linked to a satellite ground station antenna. This COPSK was used in a series of tests with an Intelsat V-A satellite. Its technique for coding analog radio waves markedly improved the information capacity and lowered the error rate of satellite communications.

COMSAT Laboratories donated this artifact to the Museum in 1999.