AUTOMATIC MOBILE RADIO TELEPHONE SYSTEM

摘要

An automatic mobile radio telephone system employs a number of mobile subsets interconnectable through a radio relay station. The station includes two or more duplex channels and marks a selected free channel with a tone fi and transmits at a reduced power. A calling mobile set sends out a tone fd and the relay station in response stops sending tone fi and starts transmitting tone fd at full power. Free sets in standby condition on fi catch fd and wait for the called number. Sets that are not concerned with the call search for another channel marked fi by the station, since the first said channel has been taken by the call. Signals from a set cannot be received directly by other sets, and secrecy of each communication is insured.