Multiple sensor intrusion detection system
First Claim
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1. An intrusion detection system comprising:
- a control unit coupled to a multi-conductor cable extending along a predetermined path in a facility to be protected;
a mode selector coupled to said control unit and providing mode control signals which are at respective signal levels corresponding to selected display modes of sensor indicators for control of the operating display mode of the sensor indicators;
one or more intrusion sensors associated with the sensor indicators and connected to said cable and operative to provide an alarm signal upon intrusion detection;
alarm means coupled to said control unit and operative to denote an alarm condition detected by one or more of said intrusion sensors;
for each of said sensors, an interface circuit coupling its sensor to said cable and operative in response to the mode control signals received on one line of said cable from said control unit to determine the display mode of the sensor indicator, and operative in response to alarm signals from said sensor to convey an alarm signal on the same line of said cable to said control unit for actuation of said alarm means irrespective of the selected display mode of the sensor indicator specified by the mode control signals.
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Abstract
A multiple zone intrusion detection system in which a plurality of intrusion sensors can be readily converted into the system without system modification, and in which mode control signals from a central control unit and alarm signals from the sensors are both conveyed on a single conductor of the system cable. Each sensor has an associated interface module which permits coupling of different types of sensors to the system and sharing of a single conductor for mode control signals and alarm signals.
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Citations
9 Claims
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1. An intrusion detection system comprising:
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a control unit coupled to a multi-conductor cable extending along a predetermined path in a facility to be protected; a mode selector coupled to said control unit and providing mode control signals which are at respective signal levels corresponding to selected display modes of sensor indicators for control of the operating display mode of the sensor indicators; one or more intrusion sensors associated with the sensor indicators and connected to said cable and operative to provide an alarm signal upon intrusion detection; alarm means coupled to said control unit and operative to denote an alarm condition detected by one or more of said intrusion sensors; for each of said sensors, an interface circuit coupling its sensor to said cable and operative in response to the mode control signals received on one line of said cable from said control unit to determine the display mode of the sensor indicator, and operative in response to alarm signals from said sensor to convey an alarm signal on the same line of said cable to said control unit for actuation of said alarm means irrespective of the selected display mode of the sensor indicator specified by the mode control signals. - View Dependent Claims (2, 3, 4, 5)
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6. For use in an intrusion detection system in which a plurality of intrusion sensors are coupled via a system cable to a central control unit, an interface module coupling each sensor to said cable and comprising:
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first means operative in response to mode control signals on one line of said cable from said central control unit for providing selected control signals for energizing sensor indicators associated with the intrusion sensors in accordance with the selected mode; said mode control signals being respective signal levels corresponding to selected display modes of the sensor indicators denoting present and past occurrence of alarm signals produced by the associated sensors; and means operative in response to intrusion detection by said sensors to provide an alarm signal on the same line of said cable for communication to said central control unit to cause an alarm indication at said central control unit irrespective of the selected display mode of the sensor indicators specified by the mode control signals. - View Dependent Claims (7, 8)
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9. For use in an intrusion detection system in which a plurality of intrusion sensors are coupled via a system cable to a central control unit, an interface module coupling each sensor to said cable and comprising:
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first means operative in response to mode control signals on one line of said cable from said central control unit for providing selected control signals for energizing sensor indicators associated with the intrusion sensors in accordance with the selected mode; said mode control signals being at respective signal levels corresponding to selected display modes of the sensor indicators denoting present and past occurrence of alarm signals produced by the associated sensors; and means operative in response to intrusion detection by said sensors to provide an alarm signal on the same line of said cable for communication to said central control unit to cause an alarm indication at said central control unit irrespective of the selected display mode of the sensor indicators specified by the mode control signals; said first means including comparator means operative in response to said mode control signals for providing outputs in accordance with the signal level of the mode control signals; latch means operative in response to the outputs from said comparator means for providing said selected control signals; a detector operative in response to an intrusion detection signal to provide an output signal; and second comparator means operative in response to said output signal from said detector to provide an alarm signal to said latch means and said means operative in response to intrusion detection when said output signal differs from a reference signal for said second comparator means by a predetermined amount.
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Specification