Remote monitoring and control system with all control and monitoring tones generatedat control station

Claim 1

IN A SUPERVISORY ARRANGEMENT INCLUDING APPARATUS AT A CONTROL STATION OF A COMMUNICATION SYSTEM AND APPARATUS AT A PLURALITY OF OTHER STATIONS OF SAID COMMUNICATION SYSTEM, AT EACH OF WHICH OTHER STATIONS ARE SITUATED A PLURALITY OF DEVICES EACH HAVING ONE OR OTHER OF TWO STATES IN DEPENDENCE UPON THE OPERATIVE CONDITION OF UNITS OF EQUIPMENT INDIVIDUALLY COUPLED THERETO, APPARATUS AT THE CONTROL STATION COMPRISING (A) FIRST MEANS TO RECEIVE A PLURALITY OF TONE SIGNALS OF DIFFERENT FREQUENCIES TRANSMITTED BY SAID OTHER STATIONS, (B) SECOND MEANS SELECTIVELY TO TRANSMIT FIRST AND SECOND COMMAND SIGNALS AND SAID PLURALITY OF TONE SIGNALS, (C) THIRD MEANS NORMALLY TO REGISTER INDICATIONS OF THE GENERAL OPERATIVE CONDITION OF SAID OTHER STATIONS IN DEPENDENCE UPON TONE SIGNALS RECEIVED FROM SAID OTHER STATIONS BY SAID FIRST MEANS, AND (D) FOURTH MEANS TO REGISTER INDICATIONS OF THE RESPECTIVE STATES OF THE DEVICES AT SAID OTHER STATIONS IN DEPENDENCE UPON TONE SIGNALS RECEIVED BY SAID FIRST MEANS DURING PERIODS WHEN SAID FIRST COMMAND SIGNAL IS BEING TRANSMITTED BY SAID CONTROL STATION.