US 4,308,430 AGranted

Apparatus for signalling system

AssigneesGTE Products Corporation, GTE Laboratories Incorporated

InventorsRobert J. Fahey, Robert A. Norbedo

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Abstract

Apparatus for a signalling system. The signalling system includes a remote control unit arranged to communicate with a centralized communications center. The remote control unit operates at or following a specified time of day to initiate a self-check call and to communicate data to the communications center. The communications center includes a disc unit which stores therein self-check timing data specifying the time of day at which the remote control unit is scheduled to initiate a self-check call. A computer at the communications center receives data from the remote control unit and operates in response thereto to update the self-check timing data in the disc unit to specify the time of day at which the next self-check call is to be initiated by the remote control unit. In the absence of data from the remote control unit, there is no updating of the self-check timing data. On a regular basis, the self-check timing data in the disc unit is compared with time-of-day data produced by a clock and representing the present time of day. In the event the self-check timing data in the disc unit specifies a time of day earlier by more than a predetermined amount than the present time of day, the computer operates to produce an output condition indicating a missing or late self-check call. The output conditions may be used in the preparation of a hard-copy printout for maintenance purposes.

In a signalling system, apparatus comprising:

first and second apparatus at first and second locations, respectively, and interconnected by a transmission medium for allowing communication between the first and second apparatus;
said first apparatus at the first location comprising:
first means arranged at or following a specified time of day to initiate a self-check call and to apply self-check message data to the transmission medium for transmission to the second apparatus at the second location;
said second apparatus at the second location comprising:
storage means arranged to store self-check timing data specifying a time of day at which the first means of the first apparatus at the first location is scheduled to initiate a self-check call and apply self-check message data to the transmission medium for transmission to the second apparatus;
processing means arranged to receive self-check message data generated by the first means of the first apparatus and operative when self-check message data is received thereby to update the self-check timing data in the storage means to specify the time of day at which the next self-check call is to be initiated by the first means, said processing means being operative in the absence of self-check message data from the first means not to update the self-check timing data in the storage means;
and
present time means operative to produce time-of-day data representing the present time of day;
said processing means being further operative on a regular basis to access the self-check timing data in the storage means and to compare the self-check timing data with the time-of-day data produced by the present time means and representing the present time of day, said processing means being operative if the self-check timing data in the storage means at the time of accessing the storage means specifies a time of day earlier by more than a predetermined amount than the present time of day as represented by the time-of-day data from the present time means to produce an output condition indicative of this condition.

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Abstract

Claims10