Protection signalling system having channel impedance alteration means for providing indications of remote station conditions

Claim 1

A SIGNALLING SYSTEM FOR PROVIDING AT ONE LOCATION ELECTRICAL SIGNAL INDICATIONS REPRESENTATIVE OF RESPECTIVE CONDITIONS OF A PLURALITY OF ITEMS LOCATED AT OTHER LOCATIONS AND EACH OF WHICH HAS AT LEAST TWO CONDITIONS, COMPRISING A SOURCE OF A TRAIN OF ELECTRICAL IMPULSES, A COMMUNICATION CHANNEL, MEANS AT SAID ONE LOCATION TO APPLY SAID TRAIN OF ELECTRICAL IMPULSES TO SAID CHANNEL, SIGNALLING MEANS AT EACH OF SAID OTHER LOCATIONS, SAID SIGNALLING MEANS BEING CAPABLE OF BEING RENDERED RESPONSIVE TO THE CONDITIONS OF CORRESPONDING ONES OF SAID ITEMS FOR ACTING UPON SAID CHANNEL BY SELECTIVELY SUBSTANTIALLY DECREASING THE IMPEDANCE OF SAID CHANNEL, SUBSTANTIALLY INCREASING THE IMPEDANCE OF SAID CHANNEL AND LEAVING SUBSTANTIALLY UNCHANGED THE IMPEDANCE OF SAID CHANNEL THEREBY, TO CONVERT SAID IMPULSES INTO DISTINCTIVE SIGNAL INDICATIONS OF THE CONDITIONS OF SAID ITEMS, CONDITIONING MEANS AT EACH OF SAID OTHER LOCATIONS FOR RENDERING THE CORRESPONDING ONES OF SAID OTHER LOCATIONS FOR RENDERING THE THE CONDITIONS OF CORRESPONDING INDIVIDUAL ONES OF SAID ITEMS, COUNTING MEANS AT EACH OF SAID OTHER LOCATIONS AND BEING COUPLED TO SAID CHANNEL FOR COUNTING THE IMPULSES BEING COUPLED TO SAID CHANNEL FOR COUNTING THE IMPULSES IN SAID TRAIN, EACH OF SAID COUNTING MEANS BEING COUPLED BY SAID CONDITIONING MEANS RENDERS THE CORRESPONDING SIGNALLING MEANS RESPONSIVE TO THE CONDITION OF A CORRESPONDING ONE OF SAID ITEMS FOR A PARTICULAR INDIVIDUAL IMPULSE OF SAID TRAIN, AND MEANS AT SAID ONE LOCATION FOR DETECTING SAID DISTINCTIVE SIGNAL INDICATIONS IN SAID CHANNEL.