Alarm testing device

Claim 1

AN AUTOMATIC ALARM TESTING DEVICE COMPRISING MEANS FOR RECORDING A PLURALITY OF SUBSCRIBER NUMBERS FOR SELECTED SUBSCRIBER LINES, MEANS FOR TRANSLATING THE RECORDED SUBSCRIBER NUMBERS INTO A FORM SUITABLE FOR OPERATING A LINE CONTROL CIRCUIT, SAID LINE CONTROL CIRCUIT INCLUDING MEANS FOR OPERATING AN OFFICE SELECTOR CIRCUIT AND A DIALING AND DETECTOR CIRCUIT, SAID OFFICE SELECTOR CIRCUIT HAVING A PLURALITY OF OUTPUT CIRCUITS ONE OF WHICH IS SELECTED BY SAID LINE CONTROL CIRCUIT TO INTERCONNECT THE DIALING AND DETECTOR CIRCUIT AND EACH SUBSCRIBER LINE FOR A BUSY TEST AND RESISTANCE LEVEL MEASUREMENT, SAID DIALING AND DETECTOR CIRCUIT COMPRISING PULSING CONTACTS, A DETECTOR DEVICE, MEANS FOR ESTABLISHING THE OPERATING POINT OF THE DETECTOR DEVICE, AND MEANS FOR CHARGING THE OUTPUT CIRCUIT BEFORE THE DETECTOR IS CONNECTED THERETO, CONTACTS CONTROLLABLE BY SAID LINE CONTROL CIRCUIT TO CONNECT ALTERNATELY THE PULSING CONTACTS AND THE DETECTOR CIRCUIT TO SAID OUTPUT CIRCUIT, A TROUBLE INDICATING CIRCUIT RESPONSIVE TO THE DIALING AND AND DETECTOR CIRCUIT AND INDICATING EITHER A BUSY CONDITION OR A RESISTANCE LEVEL BELOW A PRESELECTED VALUE OF ANY SUBSCRIBER LINE, SAID TROUBLE INDICATING CIRCUIT INCLUDING A POLAR RELAY RESPONSIVE TO EITHER A BUSY CONDITION ON THE SUBSCRIBER LINE OR AN OUTPUT FROM THE DIALING AND DETECTOR CIRCUIT INDICATIVE OF A RESISTANCE LEVEL OF ANY SELECTED SUBSCRIBER LINE BELOW A PRESELECTED VALUE, MEANS RESPONSIVE TO SAID TROUBLE INDICATING CIRCUIT FOR TERMINATING THE OPERATION OF THE RECORDING MEANS, AND MEANS FOR RESTARTING THE RECORDING MEANS AND IDENTIFYING WITH AUDIO SIGNALS THE SUBSCRIBER LINE CAUSING OPERATION OF THE TROUBLE INDICATING CIRCUIT.