Abstract: An alarm system sensor (10) monitoring movement of an object (D) and placing the system into alarm when the object moves more than a predetermined distance from a predetermined position. First and second reed switches (16, 18) are located in a predetermined orientation relative to each other and in tandem to the object. Bias magnets (24, 26) are used with the reed switches. A magnet (20) is movable with the object and produces a force simultaneously sensed by both reed switches. This force maintains both reed switches in a state keeping the alarm system in a non-alarm condition so long as the object substantially remains in its predetermined position. The object, when it moves, moves toward one of the reed switches and away from the other reed switch. Movement of the object more than the predetermined distance results in the force sensed by one of the reed switches increasing and the force sensed by the other reed switch decreasing.

Abstract: A sensor alignment tool (10) for use in the installation of sensors (S), particularly a pair of sensors such as are used in a security system or the like. Once a proper location for the sensors is identified, a mounting base (12a–12d) for one of the sensors is located adjacent a surface where the sensors are to be installed. The tool is then employed with two sets (16, 20) of adjustment rods (18, 22) to properly locate and align the sensor mounting base for the other sensor. Tolerant mounting washers are used to mount both bases to the surfaces to which they are to be attached. Once the mounting bases are properly aligned, the tool is removed and the sensors installed in their respective mounting bases.

Abstract: A plate (12) is mounted to a wall, ceiling, door or window frame, and supports an object (O). Spaced openings (14) are formed in the plate. The diameter (d) of the holes is sufficiently large that a drill bit fits through the opening for a screw hole (H) to be drilled in the wall, ceiling, or frame. A flange (20) formed on the face (22) of the plate abutting the mounting surface extends about the opening, into the opening, to provide a shoulder supporting a slotted washer (16). A slot (18) in the washer extends across the washer and has a length (l) corresponding to the diameter of the opening formed by the shoulder. A washer is placed in each opening and rotated until the respective screw holes are exposed by the slot. Now, when screws or other fasteners are inserted into the holes through the slots, the object is properly oriented or aligned, regardless of screw hole locations.

Abstract: A video security system (10) monitors a premises (F) to detect unwanted intrusions onto the premises. A site control unit (12) obtains and evaluates the images to determine if an intrusion has occurred, and provides an indication if an intrusion is detected. A central station (CS) includes a plurality of workstations (106), and a central alarm computer (104). The computer is responsive to an alarm indication to cause video images, and audio, to be transmitted to the central station for presentation at one of the workstations selected by the computer. Additionally, the computer supplies site specific data to the workstation for display with the video images. Control signals from the workstation back to the site are routed through the computer.

Abstract: A site control unit (12) located at a premises (F) processing video images obtained from a plurality of cameras (22) located about the premises and relaying the presence of a real intrusion to a central station (CS). The site control unit has an image acquisition module (24) receiving video images from the cameras. An image processor (30) processes the images to eliminate possible causes of false alarms of an intrusion and reliably detecting actual intrusions. The processor includes video masking (32) to filter known motion present within a scene, detection (34) detecting movement in unmasked portions of the scene, and recognition (36) classifying the cause of the movement. An indication of an intrusion is given only if the cause is one of a class of predetermined causes representing an intruder on the premises, or an unknown cause. A video recorder (38) records images of the actual intrusion and supplies recorded images to a security system operator (O) who informs authorities of in intrusion.

Abstract: A workstation (106) for a security system (10) includes a first video display (602a) displaying status information of video equipment (22) used at the premises to perform the surveillance. A second video display (602b) displays a plurality of thumbnail images of an intrusion scene. A third video display (602c) displays a snapshot image from which one of said the thumbnail images is derived. The snapshot is displayed upon the thumbnail image derived from the snapshot being selected by a workstation operator. A fourth video display (602d) displays data relating to the premises, identifying the location on the premises where the intrusion occurred, who should be contacted about the intrusion, etc.

Abstract: A video security system (10) monitors a premise (F) to detect unwanted intrusions onto the premises. A plurality of cameras (22) located about the premise supply video images of scenes to a processor (12) located which processes the images to detection motion in a scene and classify the source of the motion. Only if the source is determined be one of a predetermined class of causes, is an indication provided to an alarm unit (16). The alarm unit, which is also connected to a plurality of conventional sensors (S1-S3) is responsive to the indication to cause the processor to transmit authenticated video images of the scene in which the motion is detected to a central station (CS). There, a video server (102), in conjunction with an alarm computer (104), enables the images to be displayed at a selected workstation (106) for viewing by an operator (O). Besides video, audio and relevant site data is also made available to the operator at the workstation.

Abstract: A security system (S) monitors displacement between a first unit (20) mounted on a door or window frame, and a second unit (21) mounted in the door or window, adjacent the first unit. An analog signal (Sx) created at one of the units is monitored at the other unit. A least one characteristic of the signal provides an indication as to the relative position of the units, and a nominal signal characteristic value represents a nominal position of one unit relative to the other unit for a predetermined set of conditions. On at least one side of the value is a range of signal characteristic values representing a range of acceptable motion through which one unit may move relative to the other unit without putting the system into an alarm condition. The total range of signal characteristic values representing the acceptable range of motion defines a window whose size is maintained so long as the one unit moves relative to the other unit within the window.

Abstract: An alarm system includes a controller (20), a plurality of transponders (23-26), and a transducer (50) connected to one of the transponders (23). A voltage reference which is preferably earth ground is established for the entire alarm system. A local loop comprises a pair of electrical conductors (72, 73) connecting the transducer and transponder. The transponder includes a comparator (70, 80, 80-82) having a fixed reference input and a second input which is the voltage level on the local loop. If a ground fault or other abnormal condition occurs, this is sensed by the comparator and an indication provided a loop status portion (60a) of the transducer. The controller includes a communications module (27) by which each transponder is addressed, and the transponder includes an output response portion (60b) by which the transponder identifies itself to the controller as the transponder at which the ground fault or other abnormal condition has occurred.

Abstract: A security system (40) monitoring displacement between a first, fixed unit (20) and a second, movable unit (21) normally in close proximity to each other. A code generator (51) in the first unit (20) generates a coded electrical signal (Sc) supplied to an optical transducer (24) that converts the signal into an optical signal transmitted at the second unit. A transducer (34) in the second unit receives the transmitted signal, converts it back into an electrical signal now supplied to a code generator (56) in the second unit This generator determines if the electrical signal corresponds to the coded signal. If so, this second code generator generates a second coded electrical signal which is supplied to a transducer (35) in the second unit that converts the signal into an optical signal transmitted back toward the first unit. A transducer (28) in the first unit receives this reply signal and converts it back into an electrical signal.

Abstract: A housing assembly (20) for protecting electronic components. An enclosure (21) is open at one end (22). Electronic components are housed in the enclosure. A bung member (25) is insertable into the open end of the enclosure to seal the enclosure. The member defines a channel (27) and a spreader element (28) is insertable into the channel. The spreader element is formed to cause the bung member to expand upon insertion of the spreader to seal the enclosure against moisture and contaminants.

Abstract: An alarm system including a sensor for providing an output signal upon sensing a given condition, an alarm unit for providing an alarm signal on receipt of the output signal, and a timer, coupled between the sensor and the alarm unit, which is reset to a preset count each time it receives an indication that the sensor has detected the given condition where the timer is allowed to count down from a preset count while no sensor is providing output signals and an arming signal is generated by the timer when it completes the countdown.

Abstract: An alarm system has a controller which communicates over a conductive path with a remote module. An indicating device, such as an alarm bell, strobe light, audible horn or other device is coupled to the remote module and activated when a control signal is received from the controller. A rechargeable battery is provided in or adjacent the remote module, and acts as a reservoir for the power to energize the indicating device upon connection. The remote module receives charging current over the conductive path from the controller, and this current is very low, substantially less than the current level required to energize the bell, horn, or strobe. A constant power dc-to-dc converter is provided to charge the battery at the appropriate rate, while drawing a substantially lesser amount of power from the controller. Both the rechargeable battery and the indicating device are supervised, and any malfunction reported to the controller.

Abstract: A relay supervision system is disclosed to check the presence and operability both of a relay and the associated circuitry located at a position remote from the control unit which effects the supervision. The supervision is accomplished by pulsing the relay with energy at a volt-time integral less than that required to energize the relay and displace a contact set, but sufficient to cause current flow through the winding and its associated circuit components. If the relay includes two separate windings, each winding can be separately pulsed at different times, the relay state determined, and both windings effectively supervised without changing the position of the contact sets operated by the windings.

Abstract: A security system provides for bidirectional communication between a controller and a plurality of addressable transponders. At least one transponder includes a sensor circuit for detecting motion, which motion is indicated by the transponder signalling back to the controller. During a walk test the controller sends a signal back to the transponder, completing the circuit for the visible output indicator so that subsequent motions during the walk test sequence will be immediately displayed at the transponder, without necessitating successive communication through the loop including the controller. In systems where the controller itself reports upwardly in a hierarchy of units, the walk test can confirm operability of the entire system, including other condition-indicating signals.

Abstract: A mounting frame for supporting several printed circuit boards in abutting relationship includes a pair of side frame members. At least some of the printed circuit boards have slots along or near the side edges, through which screws extend into the side frame members. The screw heads extend over and retain the printed circuit boards in position. When the screws are loosened for some of the boards, those boards can be displaced from each other but not removed from the frame. Additional loosening of one set of screws allows the removal of that one board, even if that board is not the last board in the run of boards. Cylindrical bores are provided in at least one of the side frame members to afford pivotal mounting of the frame-and-card set in an enclosure. When the frame-and-card assembly is pivoted outwardly, an additional set of cards can be mounted on the back of the frame.

Abstract: A security alarm system includes a transponder having a housing enclosing both a sensor and associated circuit means in a unitary package. The housing base includes barrel-shaped connectors, and a pc board carrying the communications components is carried by the housing cover. Flag-like connectors mate with the barrel-shaped connectors when the cover is attached to the base, and the connectors give both good mechanical indexing and retention, and effective electrical contact. Removal of the cover from the base breaks the electrical contact and thus breaks continuity back to the system controller, indicating someone has tampered with the system.

Abstract: A system for debouncing a switch circuit includes a sample circuit for providing an initial determination of the switch status, and a debounce circuit connected to operate on the output of the sample or sensing circuit to verify the actual switch status by providing a confirmation signal. The system of the invention accumulates a count related either to the rate at which the sample circuit operates, or the actual changes in state indicated by latches coupled to the sample circuit. If the count accumulates to a predetermined number before being cleared by a confirmation signal verifying the switch status, then the irregular operation is signalled. This identifies a continuous, rapid alternation between different switch states without a confirmation of an actual state change, which would otherwise be undetected by system operation.

Abstract: An alarm system includes a controller and a plurality of transponders having different addresses. Certain of the transponders include switch means for monitoring conditions, and latch circuits to retain memory of the switch conditions. The controller includes means for positive recognition of a latched alarm or trouble condition in any transponder, before the clear-alarm signal or clear-trouble signal is sent from the controller to restore the alarm circuits to their original states. This insures that an alarm or trouble condition at a transponder is not "missed" by inadvertent clearing before a positive recognition is registered in the controller.

Abstract: An independent transmitter/receiver, or a transponder in a communication system, receives signals distorted by outside, unwanted conditions such as noise, line capacitance, and so forth. The status of a switch is checked at periodic times, by pulsing, rather than by continuous current flow, to conserve power. The invention includes a debounce circuit for monitoring the switch status; the debounce circuit is adjusted by a debounce select signal received from outside the transmitter/receiver. In addition a sensing circuit is coupled between the switch being monitored and the debounce circuit. The sensing circuit also has its sensing operation adjusted as a function of the debounce select signal. This allows for accurate monitoring of the switch condition, notwithstanding noise, line capacitance and other factors.