Abstract: A cellular backup system is provided for a standard security alarm network, so that upon the inoperativeness of the telephone land line, automatic switch over to the cellular system is achieved, so that a digital communicator or telephone tape dialer may still transmit its distress call to a central alarm station, via the cellular system. A line fault monitor is provided which automatically detects the outage of the land-based telephone system which, in turn, provides an output signal to a latching relay which causes the activation of a pair of switching relays to automatically switch the connection of the alarm communicator from the DB-8 cord of the land-based system to a cellular interface coupled to a conventional cellular transceiver of a cellular system. The switching relays are latched in the state connecting the alarm communicator to the cellular backup system and held in such a state, regardless of the state of the land-based system, as long as a manual rest switch has not been used.
Type:
Grant
Filed:
August 5, 1987
Date of Patent:
December 12, 1989
Assignee:
Norbert W. Zawacki
Inventors:
Dennis B. Dop, Michael G. Freitag, Norbert W. Zawacki