Signalling systems

Claim 1

A SIGNALLING SYSTEM COMPRISING: OPERATOR STATION MEANS FOR SELECTING AND TRANSMITTING DISTINCTIVE FUNCTION COMMAND SIGNALS EACH COMPOSED OF A SAFETY TONE SIGNAL AND A GIVEN NUMBER OF SUCCESSIVE CONTROL TONE SIGNALS IN A PREDETERMINED TIMED RELATIONSHIP THEREWITH; AND REMOTE STATION MEANS FOR RECEIVING, SELECTING AND TRANSLATING SAID FUNCTION COMMAND SIGNALS TO PROVIDE A PRESELECTED ONE OF A PLURALITY OF FUNCTIONS IN ACCORDANCE WITH THE RECEIVED FUNCTION COMMAND SIGNAL, SAID MEANS INCLUDING; (A) MEANS FOR RECEIVING SAID FUNCTION COMMAND SIGNALS AND PROVIDING AN OUTPUT CORRESPONDING TO THE SAFETY TONE AND CONTROL TONES SELECTED AT SAID OPERATOR STATION, (B) MEANS FOR DIRECTING THE OUTPUT OF SAID RECEIVER MEANS TO A PLURALITY OF SEPARATE CHANNELS EACH INCLUDING FREQUENCY SELECTIVE MEANS ADAPTED TO PASS ONLY A PRESELECTED ONE OF SAID SAFETY TONE AND CONTROL TONE SIGNALS SO THAT A SAFETY TONE CHANNEL AND A NUMBER OF CONTROL TONE CHANNELS ARE PROVIDED; (C) OUTPUT MEANS ASSOCIATED WITH EACH OF SAID SEPARATE CHANNELS; (D) MEANS ASSOCIATED WITH SAID SAFETY TONE CHANNEL ARRANGED TO CAUSE THE OUTPUT MEANS THEREOF TO REMAIN ENERGIZED FOR A PREDETERMINED TIME PERIOD AFTER ITS INITIAL ENERGIZATION RESULTING FROM APPLICATION OF THE SAFETY TONE TO SAID SAFETY TONE CHANNEL; (E) STORAGE MEANS, ONE ASSOCIATED WITH EACH OF SAID CONTROL TONE CHANNELS; (F) AND MEANS RESPONSIVE TO SAID SAFETY TONE FOR CONTROLLING EACH OF SAID STORAGE MEANS SO THAT THE PRESENCE OF THE CONTROL TONE SIGNAL ASSIGNED TO A GIVEN CONTROL TONE CHANNEL IS OPERATIVE TO ALLOW THE OUTPUT MEANS THEREOF TO ASSUME ITS ENERGIZED CONDITION.