Binary code selective calling system having synchronized clock oscillators at the transmitter and receiver

Claim 1

A SELECTIVE CALLING SYSTEM, COMPRISING A TRANSMITER, A FIRST SERIAL SHIFT REGISTER INCLUDING MEANS FOR SELECTING AND ENTERING THEREIN A PARTICULAR NUMBER IN THE FORM OF A PLURALITY OF BINARY DIGITS, SAID NUMBER CONSITUTING THE ADDRESS OF THE STATION TO BE CALLED, A CLOCK OSCILLATOR FOR SUPPLYING TIMING SIGNALS TO SAID FIRST REGISTER, MEANS FOR MODULATING THE SIGNAL OUTPUT OF SAID TRANSMITTER IN ACCORDANCE WITH THE SERIAL OUTPUT OF SAID FIRST REGISTER, A RECEIVER INCLUDING MEANS FOR DETECTING THE MODULATION OF SAID TRANSMITTER SIGNAL TO REPRODUCE AT THE RECEIVER THE SERIES OUTPUT OF SAID FIRST SHIFT REGISTER, A SECOND CLOCK OSCILLATOR AT SAID RECIEVER, MEANS CONTROLLED BY SAID REPRODUCED OUTPUT OF SAID FIRST REGISTER FOR SYNCHRONIZING THE PHASE SAID SECOND CLOCK OSCILLATOR WITH SAID FIRST CLOCK OSCILLATOR UPON EACH APPEARANCE OF A PARTICULAR BINARY DIGIT, A SECOND SERIAL SHIFT REGISTER RECEIVING BOTH TIMING SIGNALS FROM SAID SECOND CLOCK OSCILLATOR AND THE OUTPUT OF SAID RECIVER DETECTING MEANS FOR SHIFTING SAID OUTPUT INTO SAID SECOND REGISTER, MEANS FOR CLEARING SAID SECOND REGISTER AT THE COMMENCEMENT OF TRANSMISSION BY SAID TRANSMITTER, MEANS FOR INDICATING THE STORAGE OF A COMPLETE BINARY NUMBER IN SAID SECOND SHIFT REGISTER, AND MEANS OPERABLE UPON THE STORAGE OF A COMPLETE BINARY NUMBER IN SAID SECOND REGISTER FOR TESTING SAID STORED NUMBER AGAINST THE PARTICULAR BINARY NUMBER REPRESENTING THE STATION ADDRESS AND FOR INDICATING A CALL IF THE TEST IS TRUE.