Communication system

Claim 1

A PAY TV SYSTEM FOR DETERMINING THE OPERATION CONDITION OF EACH OF A PLURALITY OF SUBSCRIBER STATIONS COMPRISING, IN COMBINATION, A CENTRAL STATION; A PLURALITY OF SUBSCRIBER STATIONS; WIRE MEANS EXTENDING FROM SAID CENTRAL STATIONS TO EACH OF SID SUBSCRIBED STATIONS; AUDIO MEANS FOR TRANSMITTING AN AUDIO SIGNAL TO SAID SUBSCRIBER STATIONS VIA SAID WIRE MEANS; SIGNAL GENERATING MEANS CONNECTED TO SAID WIRE MEANS AT EACH SUBSCRIBER STATION PRODUCING AN IDENTIFICATION SIGNAL OF A PREDETERMINED FREQUENCY DIFFERENT FROM THE FREQUENCIES OF THE SIGNAL GENERATING MEANS AT TH OTHER SUBSCRIBE STATIONS; TRANDUCER MEAN AT EACH SUBSCRIBER STATION FOR REPRODUCING ANAUDIO SIGNAL; SWITCH MEANS AT EACH SUBSCRIBER STATION MOVABLE BETWEEN A FIRST POSITION IN WHICH SID SWITCH MEANS MAKES THE SIGNAL GENERATING MEANS AT SAID SWITCH MEANS STATION OPERATIVE AND OPENS A CIRCUIT FROM SAID WIRE MEANS TO THE TRANSDUCER MEANS AT SAID SUBSCRIBER STATIOIN AND A SECOND POSITION IN WHICH SAID SWITCH MEANS MAKES SAID SIGNAL GENERATING MEANS INOPERATIVE AND CLOSES A CIRCUIT FROM SAID WIRE MEANS TO SAID TRANSDUCER MEANS SO THAT IN THE FIRST POSITION OF SAID SWITCH MEAN AN IDENTIFICATION SIGNAL IS TRANSMITTED FROM SAID SIGNAL GENERATING MEANS VIA SAID WIRE MEANS TO SAID CENTRAL STATION AND AN AUDIO SIGNAL IN SAID WIRE MEANS IS NOT REPRODUCED BY SAID TRANDUCER MEANS AND IN THE SECOND POSITION OF SAID SWITCH MEANS AN IDENTIFICATION SIGNAL IS NOT TRANSMITTED FROM SAID SIGNAL GENERATING MEANS TO SAID CENTRAL STATION AND AN AUDIO SIGNAL IN SAID WIRE MEANS IS REPRODUCED BY SAID TRANSDUCER MEANS; AND INDICATING MEANS AT SAID CENTRAL STATION CONNECTED TO SAID WIRE MEANS FOR INDICATING THE POSITION OF THE SWITCH AT EACH SUBSCRIBER STATION THEREBY INDICATING THAT THE ASSOCIATED TRANSDUCER MEANS IS CONNECTED TO SAID WIRE MEANS.