Multiple channel radio telephone system

Claim 1

A MULTIPLE CHANNEL TWO-WAY RADIO TELEPHONE SYSTEM IN WHICH A PLURALITY OF UNIT STATIONS SELECTIVELY EMPLOY ANY OF A PLURALITY OF RADIO CHANNELS FOR COMMUNICATION WITH AT LEAST ONE BASE STATION, INCLUDING THE COMBINATION OF MEANS AT SAID BASE STATION FOR GENERATING A MARKING SIGNAL ON A SELECTED ONE OF SAID PLURALITY OF CHANNELS UPON WHICH A NEXT SUCCESSIVE COMMUNICATION IS TO TAKE PLACE, MEANS ASSOCIATED WITH EACH OF SAID UNIT STATIONS FOR SCANNING SAID PLURALITY OF CHANNELS IN SEQUENCE, EACH OF SAID UNIT STATIONS INCLUDING MEANS RESPONSIVE TO THE APPEARANCE OF SAID MARKING SIGNAL FOR CAUSING SAID SCANNING MEANS TO COME TO REST UPON SAID SELECTED CHANNEL, MEANS AT SAID BASE STATION FOR SHIFTING THE FREQUENCY OF SAID MARKING SIGNAL AT THE COMMENCEMENT OF OF THE SIGNALLING OF A UNIT STATION FROM SAID BASE STATION, AND MEANS AT EACH OF SAID UNIT STATION RESPONSIE TO SAID SHIFT IN MARKING SIGNAL FREQUENCY FOR INHIBTING A UNIT STATION FROM INITIATING A CALL DURING THE SIGNALLING OF THE UNIT STATION FROM SAID BASE STATION.