Alarm annunciator including detection of breaks, grounds, and a break followed by a ground on a monitored line

Claim 1

IN A ELECTRICAL PROTECTION SYSTEM IN WHICH A REMOTE PLACE IS COUPLED TO A STATION THROUGH A CURRENT CARRYING COMMUNICATION LINE AND IN WHICH SELECTED OCCURRENCE AT SAID REMOTE PLACE ARE SIGNALLED TO SAID STATION SELECTIVELY THROUGH CHANGES IN CURRENT FLOW IN SAID LINE FROM A NORMAL VALUE TO A FIRST VALUE, THROUGH CHANGES IN CURRENT FLOW IN SAID LINE FROM SAID NORMAL VALUE TO A SECOND VALUE AND BY A SHORT DURATION CHANGE IN CURRENT FLOW IN SAID LINE FROM SAID NORMAL VALUE TO SAID FIRST VALUE FOLLOWED IMMEDIATELY BY A CHANGE IN CURRENT FLOW IN SAID LINE TO SAID SECOND VALUE, AN ANNUNCIATING CIRCUIT AT SAID STATION COMPRISING: (A) FIRST AND SECOND SIGNAL INDICATING DEVICES; (B) FIRST AND SECOND NORMALLY OPEN ENERGIZING CIRCUITS COUPLED, RESPECTIVELY, TO SAID FIRST AND SECOND SIGNAL INDICATING DEVICES AND EACH BEING ARRANGED, WHEN CLOSED, TO OPERATE THE CORRESPONDING SIGNAL INDICATING DEVICE; (C) FIRST CURRENT RESPONSIVE MEANS COUPLED TO SAID LINE AND BEING RESPONSIVE TO A CHANGE IN CURRENT FLOW IN SAID LINE TO SAID FIRST VALUE COMPLETE SAID FIRST ENERGIZING CIRCUIT; (D) FIRST DELAY MEANS COUPLED TO SAID LAST MENTIONED MEANS AND ARRANGED TO DELAY COMPLETION OF SAID FIRST ENERGIZING CIRCUIT FOR A FIRST TIME INTERVAL; A CHANGE IN CURRENT FLOW IN SAID LINE TO SAID NORMAL VALUE BEFORE THE END OF SAID FIRST TIME INTERVAL PREVENTING COMPLETION OF SAID FIRST ENERGIZING CIRCUIT; (E) SECOND CURRENT RESPONSIVE MEANS COUPLED TO SAID LINE AND BEING RESPONSIVE TO A CHANGE IN CURRENT FLOW IN SAID LINE TO SAID SECOND VALUE TO COMPLETE SAID SECOND ENERGIZING CIRCUIT; (F) SECOND DELAY MEANS COUPLED TO SAID LAST MENTIONED MEANS AND ARRANGED TO DELAY COMPLETION OF SAID SEC-