U.S. results of TDMA field trails

Through its participation in the INTELSAT TDMA/DSI field trials in 1977-1979, COMSAT established that TDMA/DSI provided service quality acceptable to the U.S. subscriber. The prototype TDMA/DSI terminals functioned sufficiently well to validate the INTELSAT TDMA concept. However, problems encountered with the prototype terminals indicated that they would be unsuitable for commercial use in the operational environment. In the second round of field trials, COMSAT developed and tested simplified TDMA/DSI terminals to validate design concepts that could be used in the operational TDMA system to come. Testing of the simplified terminals in a simulated operational environment showed them to be simple to operate and capable of meeting the varying requirements of the international communications network.