Abstract: A method for asynchronous transmission of communication data between periodically blanked terminals separated by an unknown distance is disclosed. A bursted signal is transmitted from a first terminal with a burst time tB and a burst cycle period T. The bursted signal is received at a second terminal. A bursted response signal is transmitted from the second terminal to the first terminal. The bursted response signal has a burst cycle period of T/2 and includes a pair of response bursts, with each burst in the pair having a burst time tA?T/2?tB. Each burst in the pair of response bursts carries an identical data payload. At least one of the response bursts is received at the first terminal.

Abstract: A fault tolerant three port communications module has two control ports for receiving commands from two computers, and a communications port for transferring data over a communications channel in response to the commands. Each control port includes a select line which carries a select signal with true and false states, mode lines which carry codes that represent the commands, and a write line which carries a respective pulse in sync with each of the codes. The select line, mode lines, and write line of each control port are coupled in the module to a respective inter-processor command decoder having a lead stage and a trail stage.