Condition-responsive system for impressing distinctive frequency alarm tone on transmission line

Claim 1

ALARM APPARATUS FOR INSTALLATION AT A PREMISES TO BE PROTECTED AND FOR GENERATING AN ALARM SIGNAL INDICATIVE OF DISTURBANCE AT A POINT ON SAID PREMISES WHICH COMPRISES, A PLURALITY OF SWITCH MEANS FOR RESPECTIVE INSTALLATION AT LIKE PLURAL POINTS IN SAID PREMISES, THE SWITCH MEANS OF SAID PLURALITY HAVING A FIRST CONDUCTIVE STATE AND A SECOND NON-CONDUCTIVE STATE, FIRST AND SECOND LEAD LINES ADAPTED FOR CONNECTION TO A SOURCE OF ALTERNATING ELECTRIC POWER, ALARM INDICATING MEANS, THE SWITCH MEANS OF SAID PLURALITY BEING CONNECTED IN COMMON FROM SAID FIRST LEAD LINE TO SAID SECOND LEAD LINE BY WAY OF SAID ALARM INDICATING MEANS TO ENERGIZE SAID INDICATING MEANS UPON SHIFTING OF ONE SWITCH MEANS OF SAID PLURALITY BETWEEN SAID STATES, A SOURCE OF DIRECT CURRENT BIASING POTENTIAL, FIRST RELAY MEANS, MEANS OPERATIVELY BIASED BY SAID DIRECT CURRENT SOURCE AND OPERABLE FOR GENERATING AN ELECTRICAL SIGNAL OF FREQUENCY DISTINCTIVE TO SAID APPARATUS, SAID FRIST RELAY MEANS BEING CONNECTED IN SERIES CIRCUIT WITH SAID FIRST AND SECOND LINES FOR OPERATION UPON CONNECTION OF SAID LINES TO A SOURCE OF ALTERNATING CURRENT, AND SAID GENERATING MEANS BEING RESPONSIVE TO A DIRECT CURRENT SIGNAL APPLIED THERETO FOR GENERATING SAID ELECTRICAL SIGNAL AT A DISTINCTIVE FREQUENCY, MEANS FOR APPLYING A DIRECT CURRENT SIGNAL TO SAID GENERATING MEANS IN RESPONSE TO THE SHIFTING OF A SWITCH MEANS OF SAID PLURALITY BETWEEN SAID CONDUCTION STATES AND MEANS FOR APPLYING SAID DISTINCTIVE FREQUENCY SIGNAL TO A TRANSMISSION LINE, WHEREBY DISTURBANCE AT A PROTECTED POINT ON SAID PREMISES RESULTS IN AN ALARM SIGNAL THEREAT AND TRANSMISSION OF A DISTINCTIVE FREQUENCY ALARM SIGNAL THEREFROM.