Communications: electrical – Systems – Call station
Patent
1974-12-17
1976-09-14
Caldwell, John W.
Communications: electrical
Systems
Call station
340276, 307 99, 317123, G08B 1900
Patent
active
039809951
ABSTRACT:
It is herein disclosed a closed circuit alarm system comprising a number of alarm detectors, which system comprises an amplifier coupled through condensers to a first alarm relay and which is further coupled to a second relay the arrangement being such that when an electrical signal is generated in the first relay, in response to the bridging of any of the alarm detectors, such electrical signal is amplified and applied to such second relay thereby producing by said second relay an electrical signal which is applied to the first relay which then operates for putting the alarm device in the circuit. The circuit alarm detectors, series connected with the first alarm relay, are supplemented with electrical resistance elements in such a manner that when the electrical inlet of any of the alarm detectors is bridge-connected, an electrical resistance element associated therewith is also bridge-connected, thereby originating an electrical signal which will be amplified to operate the alarm device of the alarm circuit.
REFERENCES:
patent: 3215996 (1965-11-01), Schwartz et al.
patent: 3309685 (1967-03-01), Manning
patent: 3665461 (1972-05-01), Gnagi
patent: 3778797 (1973-12-01), Killen
patent: 3813662 (1974-05-01), Lewis
Caldwell John W.
Wannisky William M.
LandOfFree
Alarm system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Alarm system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alarm system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1029355