PC replacement for operational automatic send/receive (ASR) SATCOM teletypewriters

Results of a project demonstrate that a PC-based replacement of ASRs offers advantages in several areas. One advantage is in message handling. A PC-based system could receive, store, recall, and retransmit messages. It would also allow data processing on messages and increased editing capabilities. Another advantage is the standardization in using essentially off-the-shelf PCs to replace dedicated ASRs. With the increased processing capability of the PC some of the expensive dedicated satellite terminal control processing could be done by the PC. A third advantage is that the PC system could be upgraded in capability by software modifications as requirements change, thus minimizing hardware retro-fitting. The programmed logic design for synchronous logic circuits is shown to be a much better design method than the discrete method because it is much easier to debug and maintain. A model illustrating an interface between the ARC-171 dual modem and an IBM-compatible PC clone is presented as a guideline for future work