Time multiplex telephone system with multi-frequency dialing

Claim 1

IN A COMMUNICATION SYSTEM OPERATING IN ACCORDANCE WITH THE TIME MULTIPLEX PRINCIPLE, THE COMBINATION OF INDIVIDUAL SUBSCRIBER STATIONS, A CALL MULTIPLEX TERMINAL, ELECTRONIC CALL SWITCHES OPERATIVELY CONNECTING THE RESPECTIVE SUBSCRIBER STATIONS WITH THE CALL MULTIPLEX TERMINAL, MEANS OPERATIVELY CONNECTED WITH SAID CALL SWITCHES FOR CONTROLLING THE SAME BY MUTUALLY PHASE SHIFTED CONTROL PULSES ASSIGNED TO CONNECTIONS EFFECTED THEREBY, A PLURALITY OF DIGIT RECEIVERS, ELECTRONIC SWITCHES OPERATIVELY CONNECTING SAID DIGIT RECEIVERS TO THE CALL MULTIPLEX TERMINAL, MEANS IN SAID SUBSCRIBER CIRCUIT FOR TRANSMITTING IDENTIFYING SELECTION INFORMATION, IN THE FORM OF DIGITS, BY MULTIFREQUENCY CODE SYMBOLS, MEANS IN THE SUBSCRIBER LOOP CIRCUIT FOR INTERRUPTING THE SAME TO SIGNAL DELIVERY OF SUCH A MULTI-FREQUENCY CODE SYMBOL, AND MEANS CONNECTED TO AND OPERATIVELY CONTROLLING SAID SECOND-MENTIONED ELECTRONIC SWITCHES, RESPONSIVE TO SUCH LOOP CIRCUIT INTERRUPTION, FOR EFFECTING CONNECTION OF A DIGIT RECEIVER TO THE CALL MULTIPLEX TERMINAL DURING RECEIPT OF THE DIGIT INVOLVED, FOLLOWING WHICH SUCH DIGIT RECEIVER IS OPERATIVELY DISCONNECTED THEREFROM.