Communications: electrical – Continuously variable indicating – With meter reading
Patent
1990-04-23
1991-08-27
Yusko, Donald J.
Communications: electrical
Continuously variable indicating
With meter reading
340528, 70278, H04Q 300
Patent
active
050437208
ABSTRACT:
An electronic control system for electrically operated keyless locks utilizes a matrix keyboard to supply signals to a digital lock circuit for operating a duress alarm relay circuit, a lock release delay relay circuit, an alarm shunt delay relay circuit and a tamper disable circuit. The lock release delay relay circuit and alarm shunt delay relay circuit operate off of the same signal from the digital lock circuit for differing predetermined periods of time. The tamper disable circuit upon receipt of an invalid code from the matrix keyboard inhibits further operation of the lock release delay relay circuit and the alarm shunt relay circuit for a predetermined period of time. The duress alarm relay circuit operates off of a different signal from the digital lock circuit than the other circuits and is not affected by their operation.
REFERENCES:
patent: 3633167 (1972-01-01), Hedin
patent: 3881171 (1975-04-01), Moorman et al.
patent: 4021796 (1977-05-01), Fawcett, Jr. et al.
patent: 4114147 (1978-09-01), Hile
Holloway III Edwin C.
Yusko Donald J.
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