Telephone signaling system

Claim 1

IN A TELEPHONE INTERCOMMUNICATION SYSTEM, IN COMBINATION, A FIRST GROUP OF TELEPHONE SETS EACH INCLUDING MEANS FOR GENERATING UNDIRECTIONAL PULSES CORRRESPONDING TO A DIALED DIGIT, A SECOND GROUP OF TELEPHONE SETS EACH INCLUDING MEANS FOR GENERATING MULTIFREQUENCY PULSES CORRESPONDING TO A DIAL DIGIT, A SOURCE OF RINGING CURRENT, A MULTIFUNCTION STEPPING SWITCH HAVING AN ARMATURE AND A PLURALITY OF OUTPUT TERMINALS IN COOPERATIVE RELATION THEREWITH, MEANS RESPONSIVE TO SAID UNIDIRECTIONAL PULSES FROM ONE OF SAID FIRST GROUP SETS, SAID LAST NAMED PULSES BEING INDICATIVE OF A PARTICULAR PRESELECTED ONE OF SAID SETS, FOR STEPPING SAID ARMATURE TO ONE OF SAID TERMINALS CORRESPONDING TO SAID LAST NAMED SET, MEANS RESPONSIVE TO SAID LAST NAMED MEANS FOR APPLYING CURRENT FROM SAID SOURCE TO SAID LAST NAMED TERMINAL BY WAY OF SAID ARMATURE, AND THENCE TO SAID LAST NAMED SET, BY WAY OF A CONDUCTING PATH INCLUDING LOGIC RELAYS, MEANS RESPONSIVE TO SAID MULTIFREQUENCY PULSES FROM ONE OF SAID SECOND GROUP SETS, SAID LAST NAMED PULSES BEING INDICATIVE OF SAID PARTICULAR SET, FOR STEPPING SAID ARMATURE TO A NON SET-DESIGNATING ONE OF SAID TERMINALS, AND MEANS RESPONSIVE TO SAID LAST NAMED MEANS FOR APPLYING CURRENT FROM SAID SOURCE TO SAID LAST NAMED TERMINAL BY WAY OF SAID ARMATURE, THENCE TO SAID TERMINAL CORRESPONDING TO SAID PARTICULAR SET AND THENCE TO SAID PARTICULAR SET BY WAY OF SAID CONDUCTING PATH, WHEREBY SUBSTANTIALLY COMMON RINGING FACILITATES ARE UTILIZED WHETHER A CALL IS INITIATED BY ONE OF SAID FIRST GROUP OR BY ONE OF SAID SECOND GROUP SETS.