Line repeater for telephone system using radio links

摘要

A telephone exchange communicates with a number of scattered local stations via radio links extending from a central terminal to respective peripheral installations each comprising a radio transceiver coupled via a repeater to the line loop of an associated local station. The repeater includes a constant-current generator, combined with a polarity inverter, which is controlled via a logic network in response to signals from the exchange and from the local station (detected by a sensor in the line loop) to reverse the flow of direct current for the transmission of binary pulses to the local station. In the case of a private subscriber, these pulses may be an intermittent square wave generating a ringing signal; in the case of a public pay station they may constitute commands for the collection of tokens or coins.