Local control apparatus for central station alarm system
First Claim
1. In a security alarm system including a central station for receiving security alarm signals from at least one remotely located control unit, the control unit being associated with a secured facility which has an open, relatively unsecured state and a closed, relatively secured state and which is attended by at least one authorized operator at least while in the open state, the control unit comprising:
- first means for detecting opening of the secured facility by an authorized operator;
second means for detecting closing of the secured facility by an authorized operator;
third means responsive to the first and second means for transmitting an alarm signal to the central station if the second means does not detect closing of the secured facility within a first predetermined time interval after the first means detects opening of the secured facility;
fourth means responsive to the second and third means for producing a first output indication detectable by the operator a second predetermined time interval before the end of the first time interval if the second means has not yet detected closing of the secured facility; and
fifth means responsive to the third means for allowing the authorized operator to optionally extend the first time interval prior to transmission of the alarm signal by the third means.
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Accused Products
Abstract
In a central station alarm system the alarm sensors associated with a particular subscriber'"'"'s premises are monitored by a local control unit associated with those premises and controllable by the subscriber. The local control unit automatically reminds the subscriber when he is supposed to close the premises and turn on the system. The local control unit allows the subscriber to change his expected closing time. The local control unit may also perform various other functions such as automatically cutting off power to low priority alarm sensors during a prolonged power failure, automatically cancelling any audible alarm indication silence commands when there are no alarms to silence, and automatically forming a bridge connection between the remote ends of two communication circuits when there is a break in either circuit.
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Citations
9 Claims
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1. In a security alarm system including a central station for receiving security alarm signals from at least one remotely located control unit, the control unit being associated with a secured facility which has an open, relatively unsecured state and a closed, relatively secured state and which is attended by at least one authorized operator at least while in the open state, the control unit comprising:
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first means for detecting opening of the secured facility by an authorized operator; second means for detecting closing of the secured facility by an authorized operator; third means responsive to the first and second means for transmitting an alarm signal to the central station if the second means does not detect closing of the secured facility within a first predetermined time interval after the first means detects opening of the secured facility; fourth means responsive to the second and third means for producing a first output indication detectable by the operator a second predetermined time interval before the end of the first time interval if the second means has not yet detected closing of the secured facility; and fifth means responsive to the third means for allowing the authorized operator to optionally extend the first time interval prior to transmission of the alarm signal by the third means. - View Dependent Claims (2, 3, 4, 5)
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6. The method of operating the control unit in a security alarm system including a central station for receiving security alarm signals from at least one remotely located control unit, the control unit being associated with a secured facility which has an open, relatively unsecured state and a closed, relatively secured state and which is attended by at least one authorized operator at least while in the open state, the method comprising the steps of:
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presetting a timer associated with the control unit prior to opening of the secured facility by an authorized operator; detecting opening of the secured facility by an authorized operator and decrementing the timer at regular time intervals while the secured facility is open; allowing an authorized operator to re-preset the timer while the secured facility is open and prior to expiration of the time remaining in the timer; producing an output indication detectable by the operator a predetermined time interval before the time remaining in the timer is about to expire; and transmitting an alarm signal to the central station if the secured facility has not been closed when the time remaining in the timer expires.
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7. In a combined security and fire alarm system having a local control unit and having a plurality of security alarm sensors connected to the local control unit and a plurality of fire alarm sensors also connected to the local control unit, the system being powered by commercially available alternating current electrical power and having an electrical battery for supplying electrical power to the system in the event of failure of the alternating current power supply, the improvement comprising:
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first means for monitoring the alternating current power supply and for producing a first output signal during failure of the alternating current power supply; second means responsive to the first output signal for timing the duration of the first output signal and for producing a second output signal when the first output signal duration exceeds a predetermined time interval; and third means responsive to the second output signal for turning off power to the security alarm sensors when the second output signal occurs in order to conserve remaining battery power for continued operation of the fire alarm sensors. - View Dependent Claims (8, 9)
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Specification