Communication system interconnecting telephone line and single-frequency

Abstract

A communication system for performing bidirectional communications substantially simultaneously between a telephone line and a radio communication system by using a single-frequency carrier. A base station includes a first radio transceiver and a line connector disposed between the first radio transceiver and the telephone line. A terminal station includes a second radio transceiver. Each of the first and second radio transceivers has a control unit, a transmitter unit including a signal compressor, a synchronizing signal generator and a modulator, and a receiver unit including a signal expander. The control unit sets the line connector to an interconnecting state in response to a connection request signal from the telephone line or the terminal station, while establishes a communication enabling state between the telephone line and the terminal station during a connection processing period. After the communication enabling state has been set up, a speech enabling state is established between the telephone line and the terminal station. The connection processing period is changed over to a speech period after the communication enable state has been established, to thereby allow communication between the telephone line and the terminal station.