Multichannel intercom system with common signaling channel

Claim 1

AN INTERCOM SYSTEM CONPRISING A PLURALITY OF STATIONS, A PLURALITY OF TALKING LINKS, A SIGNAL LINK, MEANS RESPONSIVE TO ONE OF SAID STATIONS GOING OFF-HOOK FOR CONNECTING SAID ONE STATION TO SAID SIGNAL LINK MEANS RESPONSIVE TO A SINGLE CALLED STATION NUMBER RECEIVED FROM SAID ONE STATION FOR CONNECTING TO SAID SIGNAL LINK THE RESPECTIVE CALLED STATION, MEANS RESPONSIVE TO A PREDETERMINED SIGNAL FOLLOWED BY A SERIES OF CALLED STATION NUMBERS RECEIVED FROM SAID ONE STATION FOR CONNECTING ALL OF THE RESPECTIVE CALLED STATIONS TO SAID SIGNAL LINK, MEANS RESPONSIVE TO THE CONNECTION OF ALL CALLED STATIONS TO SAID SIGNAL LINK FOR TRANSFERRING ALL STATIONS CONNECTED TO SAID SIGNAL LINK TO AN IDLE ONE OF SAID TALKING LINKS, MEANS FOR EXTENDING TO SAID ONE STATION A BUSY TONE SIGNAL IMMEDIATELY AFTER A CALLED STATION NUMBER IS RECEIVED IF THE RESPECTIVE CALLED STATION IS BUSY, MEANS FOR RINGING ALL CALLED STATIONS, AND MEAND FOR DELAYING THE RINGING OF ALL CALLED STATIONS WHOSE RESPECTIVE STATION NUMBERS ARE RECEIVED FOLLOWING SAID PREDETERMINED SIGNAL UNTIL AFTER ALL OF THE CALLED STATION NUMBERS IN SAID SERIES ARE RECEIVED FROM SAID ONE STATION.