Frequency-shift dial pulsing system

Claim 1

A SIGNALING SYSTEM FOR PASSING SUBSCRIBER CALL ADDRESSES OVER A TELEPHONE TRUNK LINE COMPRISING A SENDER AT THE ORIGINATING END OF SAID TELEPHONE TRUNK LINE IN WHICH THE SUCCESSIVE DIGITS OF A STORED SUBSCRIBER CALL ADDRESS ARE MADE AVAILABLE ALTERNATELY ON A PAIR OF PARALLEL LEAD SETS IN PARALLEL BINARY FORM ONE DIGIT AT A TIME, A TIMING WAVE SOURCE, ENCODING MEANS UNDER THE CONTROL OF SAID TIMING WAVE SOURCE FOR SAMPLING SAID PAIRS OF SENDER LEAD SETS ALTERNATELY TO FORM A SERIAL BINARY DATA TRAIN REPRESENTING A COMPLETE CALL ADDRESS, SAID ENCODING MEANS FURNISHING AN ADVANCE SIGNAL TO SAID SENDER AT THE END OF EACH DIGIT TO SET UP A NEW DIGIT ON THE LEAD SET JUST SAMPLED, FREQUENCY-SHIFT MODULATOR MEANS KEYED BY SAID SERIAL BINARY DATA TRAIN AND HAVING AN OUTPUT CONNECTED TO SAID TELEPHONE TRUNK LINE, A REGISTER AT THE TERMINATING END OF SAID TELEPHONE TRUNK LINE IN WHICH THE SUCCESSIVE DIGITS OF A SUBSCRIBER CALL ADDRESS ARE RECEIVED ALTERNATELY ON A PAIR OF PARALLEL LEAD SETS IN PARALLEL BINARY FORM, FREQUENCY-SHIFT DEMODULATOR MEANS HAVING AN INPUT CONNECTED TO SAID TELEPHONE TRUNK LINE FOR RECONSTITUTING SAID SERIAL BINARY DATA TRAIN, MEANS FOR RECOVERING A TIMING WAVE FROM THE RECONSTITUTED SERIAL DATA TRAIN, DECODING MEANS UNDER THE CONTROL OF THE RECOVERED TIMING WAVE FOR ALLOTTING SUCCESSIVELY TO THE PAIRS OF LEAD SETS IN SAID REGISTER THE DIGITS IN THE SUBSCRIBER CALL ADDRESS, SAID DECODING MEANS FURNISHING AN ADVANCE SIGNAL TO SAID REGISTER AT THE END OF EACH DIGIT TO CLEAR THE LEAD SET JUST ALLOTTED A DIGIT TO RECEIVE THE NEXT DIGIT, MEANS FOR PERFORMING A VALIDITY CHECK ON EACH DECODED DIGIT, AND MEANS CONTROLLED BY SAID CHECK MEANS FOR SIGNALING SAID SENDER CIRCUIT OVER SAID TELEPHONE TRUNK LINE TO RETRANSMIT THE COMPLETE CALLED NUMBER IN THE EVENT OF AN INVALID DIGIT.