COMMUNICATION SET AND METHOD

摘要

COMMUNICATION SET AND METHOD A telephone communication method provides simultaneoulsy duplex channels between respective pairs of stations over a single wire pair highway by frequency division multiplexing. Each duplex channel has a predetermined pair of carrier frequencies, but only carrier frequency pairs of channels in use for communication are present on the highway at any time. On initiating a call, a station seeks for a free channel and reserves it by generating the "go" carrier of the free channel modulated with the call sign of the desired station, and also generating an alert signal. Quiescent stations respond-to the alert by seeking a "go" carrier with call sign data and, on identifying their own call sign, generating the corresponding return carrier to set up the channel.