proceed-to-transmit signal
proceed-to-transmit signal
[prə′sēd tə tranz′mit ‚sig·nəl] (communications)
Signal returned from a distant manual switchboard over the backward signaling path, in response to a calling signal, to indicate that the teleprinter of the distant operator is connected to the circuit.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.