Abstract: A personal security system locates emergency transmissions and tracks changes in location between successive transmissions. The transmissions are repeated automatically over a predetermined time interval exceeding five minutes. A plurality of fixed receivers are provided in predetermined positions in a protected region for detecting the emergency transmissions and a central monitoring station locates the transmissions from information provided by the detecting receivers. The monitoring station tracks successive transmissions and displays multiple locations as icons on a monitor. The icons vary in size based on relative transmission time and are stacked so any overlapping icons representing more recent transmissions are on top.

Abstract: A security system includes cameras disposed for activation by components of the system to record images of activity detected by the components. The system responds to a keypad and/or communications from a public switched telephone network to present the images for viewing. A system according to the invention supports visual verification of false alarms, tracking of arrivals and departures and recording those who arm and disarm the system. Visual verification also can be used in connection with remote notifications or authorizations of entry to the secured area.

Abstract: A security system is configured to enable and disable telephone functions in response to changes in the operational state of the system, such as fully armed, partially armed and disarmed. When the system changes its operational state, it automatically sends a command to change the implementation of a telephone function, such as call forwarding. The system includes an input device for setting the system to a selected state, an interface for communicating with the telephone service provider and a controller for initiating communications through the interface and sending a command to change the telephone function.

Abstract: A security interface device, such as a keypad, includes a proximity detector sensing a human approach and operating a light source to enhance illumination of the device in response to such approach. A timing device switches the illumination source off after the expiration of a predetermined time period and the proximity detector switches said illumination source on, or enhances the illumination, in response to the detection of movement in the vicinity of the pad. The proximity detector has a short range, and the range preferably does not intercept the floor or ceiling, to reduce triggering by pets, fans, ceiling lights and other non-human sources.

Abstract: A dialer intercept module is provided in an event detection system for automatically selecting between alternative communication channels and formats based on detected characteristics of control panel signals. More specific features detect predetermined signals, such as the telephone number dialed by the panel, or the type of alarm, and determine from the predetermined signals whether to: a) send the signal as is, over a publicly switched telephone network (PSTN); or, b) translate the signal into a different format suitable for an alternative channel, such as a wide area computer network.

Abstract: A personal security system uses conversion factors that exaggerate the influence of signal strength to locate transmitting communicators. The system includes an alarm center, portable communicators for transmitting wireless signals and a plurality of fixed receivers in known positions for monitoring the transmissions and detecting the signals. Transmitted information, including signal strength, is forwarded from the receivers to the alarm center. A transmitting communicator is located by the system using the known positions and received signal strength at the detecting receivers. Conversion factors that increase with signal strength magnify its influence, so strong signals dominate the locating calculations. In addition to a calculated location of the transmitting communicator, the alarm center displays the location of a plurality of the detecting receivers, selecting between alternative displayed information depending on a comparison of the received signal strengths.

Abstract: A multi-position adjustable work stop assembly employs a traveling gauge assembly that cooperates with independently adjustable and inexpensive location stops. The gauge assembly is moveable along a fence to define a plurality of work locating positions determined by the location stops. An engagement or contact member on the gauge assembly selectively intercepts the location stops to precisely locate the gauge assembly in the desired positions. The engagement member is an arm mounted for movement between first and second positions on the gauge assembly. In the first position the engagement member intercepts the location stops when the gauge assembly is moved longitudinally on the fence. In the second position the engagement member clears the location stops during such movement.

Abstract: A security system including a hand-portable wireless communicator having two keys for selecting and executing signal transmissions that control the system. The function of each key is determined by the order in which the keys are actuated, so the first actuated key selects the mode of operation and the other key executes the transmission. Sequential actuation of the keys, first one and then the other, initiates a test. Simultaneous actuation of the keys initiates an alarm. Multiple actuation of the same key cycles through alternative modes of operation, like armed, partially armed or disarmed. Transmission of a signal representing the selected mode is then initiated by actuation of the other key. A reset mechanism reinitiates the key functions after a predetermined time interval, so the key function is determined based on an order of actuation after said reinitiation.

Abstract: A smoke detector is provided with testing apparatus for determining if its sensitivity is within a predetermined acceptable range. The testing apparatus stores in the detector a range representing acceptable sensitivities. When a test is initiated the resulting test output is compared to the sensitivity range, or its representation, and a warning signal is provided when the output is not acceptable. According to one feature, the stored representations of the acceptable range include a maximum acceptable value and a minimum acceptable value, and the warning signal indicates when the output is above the maximum or below the minimum. According to other features, the output signal is periodic at one frequency when above the maximum and at another frequency when below the minimum. The test is initiated by a magnetic reed switch and the results are immediately apparent.

Abstract: A security system having a communications link with a central control, including a local network responds: a) to central control when the central communications link is operational; and, b) to local control when the central communications link malfunctions. More specifically, the local network includes a plurality of receivers for detecting emergency communications, an alarm for issuing a perceptible warning and a local control. The local control notifies the central control when an emergency signal is detected and activates the alarm in response to direction from the central control. The local control also includes logic for directly activating the alarm when an emergency signal is detected and there is no response from central control. According to more specific features, the central control includes data for validating emergency signals and activates the alarm only after validation. The local control, on the other hand, activates the alarm without validation.

Abstract: A method and apparatus in a smoke detector for comparing an analog signal voltage to a digital alarm threshold and for converting a digital sensitivity value to an analog test voltage. The analog signal voltage is converted to a digital value by: a) charging a capacitor at a first linear rate directly proportional to the analog signal voltage, for a predetermined time period; b) discharging the capacitor at a second predetermined linear rate to a predetermined threshold; c) counting during the discharging of the capacitor to establish a digital count representing the signal voltage; and, d) comparing the digital count to a an alarm threshold stored in the detector prior to its installation. The digital sensitivity value is converted to the analog test voltage by: charging the capacitor from the first predetermined voltage, at a predetermined rate, for a time period based on the sensitivity and a calibrated conversion factor. This charges the capacitor to an analog voltage representing the sensitivity.

Abstract: A process and apparatus are provided for calibrating an individual smoke detector prior to installation so its sensitivity can be determined easily throughout its useful life. Representations of detector output signals are stored in the detector prior to installation, preferably at the time of manufacture, and used later for determining the sensitivity of the detector. The signals may represent alarm and clean-ambient conditions, or one of such conditions and the difference between them. During monitoring of the detector, after its installation, a new reading of a corresponding signal under clean-ambient conditions is sampled and the differences before and after installation are compared to determine the sensitivity of the detector when it is monitored. The detector includes electrical contacts from which a representation of detector sensitivity is available for monitoring with an external electrical probe, such as a common voltmeter.

Abstract: A security detector including an optical emitter and a controller for determining detector specific values of predetermined parameters and operating the emitter to transmit a code representing the values. The controller periodically initiates test cycles of the detector, determines the detector specific values, and operates the emitter to transmit a bit stream including an alpha-numeric code representing the values. For a smoke detector, the parameters include atmospheric density, information for determining detector sensitivity and alarm threshold. The emitted radiation is in the visible spectrum and the controller operates the emitter to transmit one code at rates perceptible to humans and another code imperceptible to humans. The imperceptible code provides machine readable information as bytes of alpha-numeric characters. Other features include a method and an optical reader for decoding and displaying the transmitted data.

Abstract: A passive infra-red, pet immune intruder detector includes upper and lower fields-of-view or zones. The detector is less sensitive to infra-red targets in the lower zones, compared to the upper zones, and the alarm threshold is set slightly above the level required to detect humans in the lower zones. Animals, which do not have access to the upper more sensitive zones are not detected in the lower relatively insensitive zones. The detector includes pyroelectric sensing elements and multi-faceted optics for directing infra-red energy onto the sensing elements from at least one lower zone, intercepting the floor plane, and at least one upper zone, extending entirely above the floor plane. The facet defining the lower zone focuses infra-red energy onto the sensing elements less efficiently than the facet defining the upper zone.

Abstract: A wearable transmitter assembly includes a housing containing a radio frequency transmitter and tamper detecting circuit that are attached to an appendage of an individual with a buckle and strap. A light emitter and a light sensor are disposed in the housing and extend to the outside of the housing through one or more apertures. The strap includes an embedded optical fiber. Attachment of the housing to the buckle positions the emitter and sensor adjacent the ends of the optical fiber in the strap to complete an optical path or circuit from the emitter around the appendage to the sensor. The housing is sealed closed, including sealant between the emitter, the sensor and the aperture, providing a water tight enclosure for said transmitter from the time of its manufacture. Attachment of the housing to the buckle completes a seal blocking contaminates, such as water, water vapor, and soap from the ends of the optical fiber, the emitter and the sensor.

Abstract: In a security system, a transmitter housing and first and second transmitter actuation elements cooperate to define thumb and finger saddles on opposite sides of the housing. The peripheral edge of the housing and the first and second actuation elements have matched configurations aligned at the thumb and finger saddles for guiding a hand to properly operate the transmitter while blocking other objects from accidental operation. The housing extends beyond the actuation elements at the ends of the elements while the actuation elements extend beyond the housing at the center of the elements. The housing has a first texture, such as a rigid plastic, while the actuation elements have a softer feel provided, for example, by an elastomeric material.

Abstract: A microwave intrusion detector is provided with a periodic signal detector that identifies periodic signals not typical of an intrusion and adjusts the alarm threshold in response such identification. The intrusion detector includes an adjustable threshold and a noise compensating circuit that actively adjusts the threshold at a first predetermined rate to mask background noise levels. The periodic signal detector modifies the adjustment, increasing the predetermined rate, when it detects a periodic signal typical of a motor, fan, florescent light or the like. The periodic signal detector also cancels or disables any pending or ongoing alarm to provide sufficient time for the threshold adjustments at the increased rate.

Abstract: A personal security system with system wide testing includes a portable transmitter that produces an emergency signal including a personal identification number and an auxiliary code. The auxiliary code may be a test bit which, when set, indicates that the emergency signal was activated in a test mode and that an emergency condition did not exist. Activation of the test mode is accomplished by the same systems required to activate the emergency signal to provide full testing. The transmitter is part of a security system including a plurality of portable transmitters and fixed receivers. The transceivers issue either an alarm activating signal or a test signal depending on the test bit in the auxiliary code. A successful test is discernible to the user from the vicinity of the transceiver.

Abstract: A personal security system including features for monitoring guard tours and other surveillance by security personnel. The security system includes a plurality of hand-portable transmitters, a plurality of fixed receivers and a control station. The transmitters are actuated to emit radio frequency signals including a class code that identifies first and second sets of the transmitters. The first set is assigned to security personnel and the second set to system subscribers. The receivers decode the signals from the transmitters and provide an output representing the receiver and the received class code. The control station identifies the location of the transmission using information from the receiver output, and records the time of the transmission. If the class code represents a security-assigned transmitter, the control station reports the information as a security function, such as a guard tour.