Alarm system with synchronous scanning

Claim 1

A SECURITY ALARM SYSTEM COMPRISING: A PLURALITY OF REMOTE STATIONS, EACH STATION INCLUDING A PLURALITY OF DETECTION ELEMENTS OPERABLE FOR SENSING PARTICULAR ALARM CONDITIONS, A REMOTE STATION STEPPING SWITCH HAVING A WIPER ARM AND A PLURALITY OF CONTACT POINTS, A SEPARATE CONTACT POINT BEING CONNECTED TO EACH DETECTION ELEMENT, MEANS RESPONSIVE TO THE OPERATION OF A DETECTION ELEMENT FOR ENERGIZING SAID STEPPING SWITCH, SUCH THAT SAID WIPER ARM STEPS IN SEARCH OF THE CONTACT POINT ASSOCIATED WITH SAID OPERATED DETECTION ELEMENT, MEANS FOR DEENERGIZING SAID STEPPING SWITCH WHEN SAID WIPER ARM IMPINGES UPON THE CONTACT POINT ASSOCIATED WITH SAID OPERATED DETECTION ELEMENT, MEANS FOR GENERATING A PULSE SIGNAL FOR EACH STEP OF SAID WIPER ARM OF SAID REMOTE STATION STEPPING SWITCH, A PAIR OF WIRES, AND MEANS FOR TANSMITTING SAID PULSE SIGNALS OVER SAID PAIR OF WIRES; AND A CENTRAL CONTROL CENTER CONNECTED TO EACH OF SAID REMOTE STATIONS BY THE PAIR OF WIRES ASSOCIATED WITH EACH REMOTE STATION, SAID CENTRAL CONTROL CENTER INCLUDING FOR EACH REMOTE STATION MEANS FOR RECEIVING EACH OF SAID PULSE SIGNALS FROM THE ASSOCIATED REMOTE STATION, A CENTRAL STEPPING SWITCH, SAID CENTRAL STEPPING SWITCH INCLUDING A WIPER ARM AND A PLURALITY OF CONTACT POINTS, EACH OF SAID CONTACT POINTS DENOTING A PARTICULAR DETECTION ELEMENT AT THE ASSOCIATED REMOTE STATION, MEANS FOR ENERGIZING SAID CENTRAL STEPPING SWITCH IN RESPONSE TO EACH PULSE SIGNAL FROM THE ASSOCIATED REMOTE STATION SUCH THAT SAID WIPER ARM OF SAID CENTRAL STEPPING SWITCH STEPS IN SYNCHRONISM WITH SAID CENTRAL STEPPING SWITCH STEPS IN SYNCHRONISM STEPPING SWITCH, INDICATOR MEANS CONNECTED TO SAID CONTACT POINTS OF SAID CENTRAL STEPPING SWITCH FOR PROVIDING A PARTICULAR INDICATION OF THE OPERATION OF SAID OPERATED DETECTION ELEMENT AT SAID ASSOCIATED REMOTE STATION, AND MEANS RESPONSIVE TO SUCH INDICATION BY SAID INDICATOR MEANS FOR GENERATING A SIGNAL TO THE ASSOCIATED REMOTE STATION, SAID SIGNAL REENERGIZING SAID REMOTE STATION STEPPING SWITCH THEREBY ALLOWING ITS WIPER ARM TO STEP IN SEARCH OF OTHER OPERATED DETECTION ELEMENTS.