Abstract: A non-defeatable magnetically actuatable switch device is shown and described for restricting access to industrial controls. The non-contact switch device employs one or more non-contact access switches, and an access key removably disposed in close proximity to each access switch. Removal or installation of an access key alters the electrical state of a corresponding access switch. A connected control unit determines a mode of operation, or grants permissions, based on the combination of access keys that are present or absent from the device. A lockable or sealable cover is provided over the access keys to limit unauthorized access. A tamper detection switch is also provided for the sole purpose of identifying foreign magnetic sources in the vicinity of the access switches to ensure that the device is non-defeatable.

Abstract: A battery-powered occupancy sensor for detecting an occupancy condition in a space comprises first and second batteries, an occupancy detector circuit, a controller, and a wireless transmitter for transmitting a first wireless signal in response to the occupancy detector circuit detecting the occupancy condition in the space. The controller and the wireless transmitter are powered by the first battery, while only the occupancy detector circuit is powered by the second battery, such that the occupancy detector circuit is isolated from noise generated by the controller and the wireless transmitter. The occupancy detector circuit draws a current having a magnitude of approximately 5 microamps or less from the second battery. The occupancy sensor transmits a second wireless signal is response to determining that the voltage of one of the batteries has dropped too low.

Abstract: An apparatus (500) can be comprised of a light source interface (503), an animate object detector (502), and a controller circuit (501) that couples to the light source interface and the animate object detector. This controller circuit is configured and arranged to, upon detecting (101) an animate object via the animate object detector, cause (103) energy as is provided via the light source interface to be only temporarily temporally intermittent in order to cause a light source that is energized by the light source interface to flash and thereby draw attention to the animate object.

Abstract: A method of sensing motion in a predetermined area is provided. The method may include using a digital output motion sensor to produce a digital output signal indicative of the presence of motion in the predetermined area. The method may further include transmitting the digital output signal along a signal path independent of analog amplification and filtering. The method may also include using a microprocessor coupled to the signal path to receive the digital output signal and to process the digital output signal.

Abstract: A position sensor having a circular transmitter coil which generates electromagnetic radiation when excited by a source of alternating electrical energy. A receiver coil has a first loop wound in a first direction around a portion of the transmitter coil and a second loop wound in a second direction opposite from the first direction around a diametrically opposed portion of the transmitter coil. In addition the receiver coil includes a first compensating coil wound in the second direction inside the first portion of the transmitter coil as well as a second compensating coil wound in the first direction inside the second portion of the transmitter coil. The first and second loops and the first and second compensating coils of the receiver coil are electrically connected in series with each other.

Abstract: An induction actuated container cover includes a control housing having a cover opening, a cover panel pivotally mounted to the control housing to pivotally move between a closed position that the cover panel covers at the cover opening and an opened position that the cover panel exposes the cover opening, and an automatic driving arrangement including a sensor mounted at the control housing for detecting a target movement of a user and an actuation unit supported in the control housing to operatively link with the sensor, wherein the actuation unit is actuated to generate a decelerating and torque enhancing force to move the cover panel between the opened and closed position in a hydraulic manner.

Abstract: An apparatus and method are provided for operation of a display device to provide a home security alarm. In one embodiment, a method includes receiving a user alarm activation command by the display device; initiating a detection mode, by the display device, based on the user command; and detecting, by a sensor of the display device, at least one of a presence and motion within a target area of the display device. The process may also include outputting an alarm signal, by the display device, based on detecting the at least one of a presence and motion in the target area.

Abstract: An obstacle detection device has an ultrasonic sensor fixed to a first side of a mount member. The ultrasonic sensor sends/receives ultrasonic wave toward/from a second side of the mount member, which is opposite to the first side thereof. At least one of a mounting surface of the ultrasonic sensor and a mounting surface of the mount member has a protrusion, which protrudes therefrom so that an end surface of the protrusion contacts the other of the mounting surfaces. The mounting surfaces of the mount member and the ultrasonic sensor face each other. The end surface of the protrusion and the mounting surface of the ultrasonic sensor are different from each other in at least one of shape and area thereof.

Abstract: A security apparatus comprising a plurality of sensing elements, each adapted to detect intrusion into protected premises, each sensing element outputs a sensing signal representing a detected event, a signal processing section for examining each sensing signal and outputting a signature for each sensing signal, a computing section for translating each signature into a normalized threat value, ranging from “0” to “1”, modifying each normalized threat values by multiplying a weighting coefficient corresponding to a type of sensing element, storing for a temporary period of time, each modified normalized threat value, and an alarm generating section for adding each of the stored modified normalized threat values, outputting an aggregate threat value and generating an alarm enable signal based upon an analysis of the aggregate threat value.

Abstract: A detection system comprising a plurality of taut wire panels having vertical detection/sensor wires. The sensor wires are tensioned to position trigger plates associated one or more of the wires. Trigger plate movement causes an actuating means to indicate a sensor wire has been moved. In one embodiment, sensor wires and portions of the panel frame have similar coefficients of thermal expansion to substantially eliminate environmental expansion effects that may result in false alarms. Linked sensor wires on adjacent panel may signal movement of entire panels. Panels are monitored by panel controllers reporting to sector controllers that report to a central command computer that automatically numbers sector and panel controllers at start-up. Bi-directional communication enables alarms and system faults to be precisely located.

Abstract: A security system for a boundary is generally shown as (1) in FIG. 1. The components comprise an elongate member (2) and a support (3) for the bar. The bar support (3) can be fitted to boundary support. A conduit (7) extends through the housing (3). The rod is surrounded by a resilient member. The boundary supports (4) and the bars (2) are in communication with a circuit monitor unit (17) and from an electromechanical disturbance mechanism (EMDM) unit for detecting security breakdown of the boundary.

Abstract: An infrared motion sensor system has an infrared (IR) sensor having a predetermined field of view, a target positioned within the field of view of the sensor which emits a spatially or temporally non-uniform pattern of IR radiation, and a processor which receives an output signal from the IR sensor, compares the received output signal to a signature temperature profile signal corresponding to the non-uniform pattern of IR radiation emitted by the target, and detects deviation of the sensor output signal from the signature temperature profile signal, indicating intervention of an object in a monitored volume between the target and sensor. The size of the target may be of the order of human size.

Abstract: A wireless security system includes a power supply and a security device in selective electrical communication with the power supply. The security device provides a security response when electrically connected with the power supply. A receiver is electrically connected between the power supply and the security device and is operable to selectively electrically connect the security device with the power supply. At least one self-energizing switch of the system includes a wireless transmitter and an energy harvester that is operable to power the wireless transmitter. The wireless transmitter emits a signal to the receiver in response to power from the energy harvester, to trigger the security response.

Abstract: An identification system combines RF identification tags with ambient condition detectors of a monitoring system. The tags could be carried by individuals in the region(s) being monitored to provide occupancy feedback to first responders in the event of an alarm condition.

Abstract: An integrated circuit implements a wireless remote sensor. The wireless remote sensor includes an antenna coupled to an energy distribution unit to allow passive collection of electrical charge. A signal processing unit couples to the energy distribution unit and modulates transmission by the antenna according to a binary code.

Abstract: A method and apparatus are provided for detecting occupancy in an area using multiple detection technologies (e.g., ultrasound and infrared sensing) to intelligently control switching of plural load circuits whereby one of the circuits is affected by photocell control. A programmable controller implements auto-on, manual-on, reversion to auto-on and override operations with respect to the separately controlled load circuits based on sensor outputs and user inputs. An improved power supply for an occupancy sensor and load control device employs a DC voltage derived from leakage AC voltage between line and ground to drive the sensors and other circuits, and a switching regulator with a switching cycle controlled by a pulse width modulated (PWM) subsystem of the apparatus, allowing synchronous, delayed or exclusive operation relative to the sensing technology such as the US transmitter.

Abstract: A security and tracking system to prevent the unauthorized use or access to machinery having hydraulic components whereby the system has a rerouting device housed in a tamperproof casing. The rerouting device might have a selective re-directional valve that can be remotely activated and monitored using wireless signal technology to direct hydraulic fluid to at least two hydraulic circuits, a control center that communicates via wireless signal technology to the rerouting device, a first hydraulic circuit that has a source of fluid, a fluid pumping means, the rerouting device, and a power take off device (PTO) and a second hydraulic circuit that has the source of fluid, the fluid pumping means, and the rerouting device. In operation the rerouting device selectively routs hydraulic fluid about the hydraulic circuit that includes the PTO, thereby rendering the hydraulic equipment functionally operable until the hydraulic fluid is rerouted to the second hydraulic circuit.

Abstract: The present invention provides a penetration detecting apparatus which is applicable for various kinds of applications. Although an interval between processing machines and the conveying of an object W is suspended to wait for processing, a muting function of the penetration detecting apparatus is effective. Another feature of the present invention is to provide a penetration detecting apparatus which can avoid the muting function continuously being activated when a trigger sensor for initiating the muting function is malfunctioning.

Abstract: A security light is provided comprising a mounting base for attachment to a support therefor; sensor means on the mounting base for detecting the presence of a person or moving object within a radial range of the sensor means and within any one of a plurality of angularly adjacent sectors radiating from the mounting base that together cover an angular field of operation of the security light. A light source and reflector assembly has an angular field of illumination at least equal to the angular field of each of the angularly adjacent sectors and is angularly movable relative to the mounting base between a plurality of positions corresponding to the plurality of angularly adjacent sectors so as to be selectively directed in a direction in which the field of illumination covers an entire sector.

Abstract: A method and system for controlling lighting in a space reduces energy consumption of the light sources by changing at least one of the color rendering index (CRI) and the correlated color temperature (CCT) while maintaining illumination levels. Preferably, the method and system sense movement of people in the space relative to light sources that light the space, and automatically and individually adjust plural solid state lighting devices that form each of the respective light sources to a first lighting condition when people are in a first position, wherein the lamps respectively emit light of a first illumination level and a first CRI at a first electrical power level, and to a second lighting condition when people are in a second position, wherein the light sources respectively emit light of the first illumination level and a smaller CRI than the first CRI and at a lower electrical power level than the first electrical power level.

Abstract: A passive microwave receiver array, operating in the one meter to sub-millimeter wavelengths range and including an internationally protected range of frequencies of varying bandwidth, may be used for fire and intrusion detection. One or more receiver array can be used to provide a plurality of frequency ranges that can be detected. In an interior installation, one or more receiver array can be placed inside a wall. In other embodiments, the receiver and array can be in the form of a hand-held or wearable device. This method and apparatus achieves high performance by exploiting conventional low noise amplification block conversion circuits and provides the detection of thermal signals through clear, smoky, misty, or environmentally untenable conditions as well as the detection of fire and intrusion events through a non-metallic wall.

Abstract: A network system including a plurality of mobile devices is provided. The plurality of mobile devices each have a sensor function and a wireless communication function, the mobile devices communicating sensor information about a target with one another and tracking the target; a target searching section configured to obtain sensor information while the plurality of the mobile devices move and for reporting the sensor information among the mobile devices by wireless communication; a target focusing section configured to, in response to one of the mobile devices detecting a target, focus a sensor on the target in cooperation with mobile devices adjacent to the mobile device detecting the target; and a target surrounding section configured to surround the target by using a plurality of mobile devices that focus their sensors on the same target.

Abstract: A secure sealed container and mounting pole house any of a variety of security equipment. Sensing equipment, a high decibel siren, and strobes simulating police lights are removably attachable to a universal mount and control circuit. A control panel connected to the circuit enables and disables the alarm, and monitors system activity.

Abstract: An entrance denial security system for detecting a fault condition at one or more entrances into a secured area representing unauthorized activity and an attempt to gain entry through the entrance. The system comprising an entrance barrier closing an entrance into a secured area; the barrier including a plurality of hollow structural elements having hollow cores forming a rigid integral barrier; an optical fiber sensor line laced through the hollow cores of the structural elements of the gate for detecting the fault condition; a processor in communication with the fiber sensor line for generating a fault signal in response to the occurrence of a fault condition and identifying the entrance where the fault condition occurred; and a communication device operatively associated with the processor for communicating the fault signal so that a proper security response can be made to the fault condition.

Abstract: A remote wellness monitoring system with universally accessible interface consists of an apparatus or home appliance unit running an embedded software program connected to a server computer via a phone line or high-speed internet. At home, the apparatus communicates with an optional set of medical health monitoring devices using wired or wireless communications methods in order to perform wellness measurements. Embodiments of the invention provide a novel user interface on the home appliance to make the system accessible to people with disabilities. The simple user interface is designed to be accessible to people who are blind or deaf or people who cannot use their hands and require an alternative interface device such as a sip & puff controller. The home unit can further monitor wellness activity of the care recipient by pegging the number of times the care recipient passes by an infra-red motion sensor.

Abstract: A method of installing a security system includes activating a security device. An air-borne identification signal is transmitted from the device in response to the activation. The identification signal identifies the activated device. The identification signal is used to ascertain a type of the device. The device is automatically wirelessly configured dependent upon the type of the device.

Abstract: The invention relates to an infrared intrusion detection device. It comprises a housing 1, a window 2, which is arranged at a front side of the housing and which is transparent for at least infrared radiation emitted by an intruder, an infrared sensor arranged inside the housing for detecting the infrared radiation emitted by the intruder. Further it comprises a light guide 7, which is arranged inside the housing, which has at least one light entrance facet and which has a plurality of light exit facets 3 being arranged at the front side of the housing. A light emitter 6 is arranged inside the housing for injecting light into the at least one light entrance facet of the light guide. A light detector is provided for detecting light reflected back into the housing by an obstacle in the vicinity of the window. A signal processing unit is arranged for triggering an alarm, when an absolute difference of the intensity of back-reflected light to a predetermined value exceeds a threshold value.

Abstract: Systems and methods are provided for detecting changes in a monitored environment. One aspect of the invention relates to a system that comprises a plurality of radio frequency (RF) sensors distributed about the monitored environment, such that each RF sensor configured to respond to an interrogation signal with a unique identifier and a radio frequency (RF) interrogator that transmits interrogation sequences of interrogations signals over a plurality of different frequency bands at one or more power levels. The system also includes a response pattern analyzer that determines response patterns for each of the plurality of RF sensors to the interrogation sequences and transmits a change detection indicator if at least one of the determined response patterns vary outside a predetermined background baseline.

Abstract: A pool safety sensing system to attempt to reduce the likelihood of drowning visually observes a zone with a camera, and if detected motion occurs, and alarm is generated. The alarm can be visible, audible, text based (email, with or without attached images, instant message) or telephonic. Alarm events can be stored for future reference. Zones of sensing or zones to ignore when monitoring may be defined in the field of view of the camera. Motion thresholds, such as size of moving object, speed of movement, can be employed to adapt to particular location requirements and types of sensing.

Abstract: Jungle canopy surveillance apparatus and method for surveillance of human presence in a jungle canopy environment includes a plurality of sensor-relay units configured to be disposed on or near the jungle floor, and configured to detect human presence and wirelessly transmit a corresponding detection signal. At least one of the sensor-relay units is configured to receive a detection signal from another sensor-relay unit and to relay the thus-received detection signal. An artificial intelligence center is configured to be disposed on or near the top of the jungle canopy, and is configured to (i) receive at least one of the detection signal and the relayed detection signal, (ii) analyze the received at least one of the detection signal and the relayed detection signal using artificial intelligence software, and (iii) transmit a corresponding report signal to a receiving platform.

Abstract: A sensing device for detecting an approaching object is composed of a sensor section that includes a detection electrode supplied with a detection source signal having a prescribed frequency and another detection electrode disposed in close vicinity to the detection electrode, a communication signal amplifier that amplifies the communication signal and outputs the amplified communication signal as an amplifier output signal, an integrator that integrates the amplifier output signal and outputs a judging signal for judging whether or not an object approaches the sensor section, and a detection sub-signal switch that is disposed between an output side of the communication signal amplifier and an input side of the integrator. A communication signal is obtained from the detection source signal that is transmitted to the other detection electrode from the detection electrode and attenuated thereat when an object approaches the sensor section.

Abstract: Embodiments of the present invention is directed to a method and system for use of ranging MW to reduce dual (MW/PIR) intrusion detector false alarms. A Doppler microwave system may be provided that is capable of detecting an object range and adjusting the sensitivity of the PIR detector to account for object size and range. Multiple range limited MW stages may be configured for different ranges to determine the general range of the moving object. Based on signal levels present on these MW stages, an approximate object range is determined. The sensitivity of the PIR is then adjusted based on a PIR sensitivity vs. object range function that is optimized to alarm on humans and ignore small animals and insects.

Abstract: An armed enclosure apparatus includes a housing to be mounted on a building to encircle a telephone junction box. A cover is provided for engagement with the housing by means of a plurality of security screws. The apparatus further includes a plurality of screw tamper switch assemblies which sense tampering with the security screws and generate a corresponding signal which is transmitted along the telephone lines to a central monitoring station.

Abstract: A system for monitoring and distinguishing occurrences along a perimeter bounded by a plurality of piezoelectric cables. The monitoring system utilizes a plurality of piezoelectric cables that generate electrical signals in response to mechanical stress events. The electrical signals from each piezoelectric cable are analyzed by a base unit to determine event classification and location. The monitoring system alerts users and connects to an existing security system to notify third-parties. The monitoring system includes functionality to communicate with a calibration unit and calibrate itself. The monitoring system also includes functionality to interface with a pet containment system.

Abstract: The present invention relates to an integrated method and system for preventing and solving problems relating to pests of any kind on a site, in a building, in a process, installation or in an area. The system involves complete digitalizing and automation of all functions necessary in order to control the pests such as surveillance, registration, alarms, regulation and remedial actions as well as generating reports etc. The aim is to make the overall effort against the pests more effective by means of fully automating all processes to the furthest possible extent.

Abstract: A telephone messaging system with active security feature is disclosed. In one form of the invention, a telephonic security and recording system includes a cordless telephone security base including electronics operable to provide telephonic and security features. The electronics a telephonic and security processor operable to process security and telephonic based processes, a memory device coupled to the processor and operable to store information associated with providing telephonic and security features. The cordless telephone security base further includes a display coupled to the processor and operable to display telephonic and security information and at least three telephonic line transceivers operable to communicate with an analog telephonic network. A wireless handset transceiver is operable to wirelessly couple the analog telephonic network to a wireless handset and at least three read/write optical compact disk drives operable to record security and telephonic information are provided.

Abstract: Intrusion detection methods and apparatus exploit the infrastructure of the building itself. The preferred embodiments use the existing power line infrastructure to provide power, data, and sensor observables to a monitoring system which is simply connected at one point, namely, the connection of the building to the city power grid. Computer network interfaces may also be used. In terms of sensors, impedance, capacitive, inductive, electric field and Radar modalities may be used.

Abstract: Improved alarm system that is able to distinguish intrusions by persons from intrusions by others, such as nonhuman animals and inanimate objects. Multiple sensors are placed in a vertically aligned array, so that each sensor monitors at a different elevation. As animals and other objects generally have different sizes and shapes than humans, the vertically spaced sensors will detect different intrusion patterns than the intrusion patterns typically generated by a human. By analyzing these different intrusion profiles and only signaling an alarm when a profile resembling an intrusion by a person occurs, a number of false alarms can be avoided.

Abstract: A dual-modality sensor for detecting a presence of a human intruder within a secure setting includes a seismic sensor for acquiring a seismic signature of a disturbance, and includes an active acoustic sensor to acquire an acoustic signature of the disturbance. A system processor is electrically connected to the seismic and active acoustic sensors to receive and process the seismic and acoustic signatures, and generate an alarm signal when the disturbance is determined to come from a human intruder. Also included is an antenna and/or hard-wire connection arranged for communicating the alarm signal. The dual-modality sensor is arranged in a sensor housing constructed to contact a surface of the secure setting. The sensor may include a battery or other means for providing electrical power.

Abstract: In one aspect, the invention comprises a device for measuring electricity usage, comprising: means for remote disconnection via power line communication; means for detection of electricity theft; means for tamper detection; and means for reverse voltage detection. In another aspect, the invention comprises an apparatus for multi-channel metering of electricity, comprising: (a) a meter head operable to measure electricity usage for a plurality of electricity consumer lines; (b) a transponder operable to transmit data received from the meter head via power line communication to a remotely located computer, and to transmit data received via power line communication from the remotely located computer to the meter head; and (c) a load control module operable to actuate connection and disconnection of each of a plurality of relays, each relay of the plurality of relays corresponding to one of the plurality of electricity consumer lines.

Abstract: A solar-infrared-rays sensing garden lamp is provided. It mainly comprises a garden lamp body with a control apparatus set inside. The control apparatus charges a power supply via the solar energy in the daytime, and provides power via the power supply in the nighttime. Therefore a infrared rays sensing circuit set on the garden lamp body at a surface thereof can sense omnibearingly in the nighttime. When the infrared rays sensing circuit senses unusual situation, it drives a corresponding lighting unit to illuminate and transmits a triggered signal to the voice control unit for driving a speaker and giving off sounds.

Abstract: Described are embodiments that detect attempts at malicious action against an installation under surveillance based on signals detected by a plurality of sensors distributed near an installation.

Abstract: A monitoring and entry system presence service provides notification about a trigger event to a user and performs actions based on user input. Interface devices equipped with client applications capable of performing actions such as VoIP calls, video calls, and the like, register with a control and session layer, which facilitates interaction with a specific presence application and an integrated presence service, such as a doorbell application and a generic presence service. Upon determining the location of a user, notification and a list of actions are provided through a watcher client application. In response to the user selection, actions are facilitated through the same network session(s).

Abstract: A system and method for monitoring a facility is provided. Generally, the system comprises monitoring tags wherein each monitoring tag emits an identifier signal unique to each monitoring tag, monitoring sensors wherein the monitoring sensors receive signals from the monitoring tags and relay the signals to one or more monitoring stations, and monitoring stations wherein the monitoring stations log and display information associated with the signals received. The monitoring station identifies possible events based on the signals received from the monitoring sensors. The monitoring station alerts staff members of the events via a graphical user interface, pagers, email, and alarms.

Abstract: A room occupancy monitoring system monitors the occupancy status of a plurality of rooms and collects and displays the room occupancy information in real time. The room occupancy monitoring system includes a plurality of room occupancy sensor devices and a server. Each of the room occupancy sensor devices is located in a corresponding one of a plurality of rooms, detects whether the corresponding one of the plurality of rooms is occupied, and generates a first signal indicating whether the corresponding one of the plurality of the rooms is occupied and a second signal indicative of the identity of the corresponding one of the rooms. The server receives the first signal and the second signal from the room occupancy sensor devices through a data communication network and displays room occupancy information of the plurality of the rooms based on the first signal and the second signal on a display device.

Abstract: An occupancy sensor includes an infrared sensor, a variable bandpass filter operably coupled to the infrared sensor and a controller operably coupled to the infrared sensor and the variable bandpass filter. The bandpass filter includes digital potentiometers adapted to control a gain of the bandpass filter, the tuning of the bandpass filter, and the ratio of a center frequency of the bandpass filter to a bandwidth of the bandpass filter. The controller includes a bandpass filter engine to control the variable bandpass filter, a Doppler shift engine to characterize the signals filtered by the variable bandpass filter, and an occupancy sensing engine to determine the presence or absence of the occupant within the defined region. The controller is adapted to filter the signals generated by the infrared sensor and process the filtered signals to determine the presence or absence of an occupant within a defined region.

Abstract: A security system for use in connection with cargo containers and other enclosed spaces. The system monitors vibrations associated with a container and detects signals representative events indicating that an unauthorized access has been made to the container. The system may be programmed with a library of event signatures, allowing different types of events to be detected. The system may be provided with a library of signatures representing a heart beating with a beat pattern and the system may be used to detect a human or other animal within the container. Alternatively, the system may be provided with a library of signatures representing piercing the container. The system may be used to monitor containers in transit. Indications of events may be stored while the container is in transit and then communicated at a security check point.

Abstract: A monitoring system includes a transmitter (102) with two transmit modules (208, 210) and a receiver (104) with two receive modules (212, 214). Each of the transmit modules (208, 210) generates an optical signal modulated at a unique frequency. The optical signals are transmitted across a roadway (112) and are detected by the receive modules (212, 214). When a vehicle (110) moves between the transmitter (102) and receiver (104), the optical signals are blocked. The receiver (104) generates timestamped make and break events corresponding to the blocking and unblocking of the signals, and these are used to determine parameters for the vehicle (110) such as velocity and vehicle classification. Because each signal is modulated at a different frequency, each receive module (212, 214) can distinguish the signals received from each of the transmit modules (208, 210), allowing the lane position of the vehicle (110) in a multi-lane roadway (112) to be determined.

Abstract: Location of an emitter using leaky cables. A two-channel receiver determines the location of an emitter by measuring the phase and/or amplitude difference between emitter signals received by leaky cables. In one embodiment, two leaky cables having different propagation velocities are used. In a second embodiment also suitable for use with fiber optic cables, two cables having the same propagation velocity are used, but have different lengths, the extra length being taken up by serpentine patterns or loops. A single cable in a loop may also be used. The leak points on the cables may be passive, or may be controlled RF switches.

Abstract: A passive optical anti-tamper system including one or more light pipes, one or more light detectors and an alarm. The light pipes each include an input end and an output end and are located within a chassis with the one or more light detectors. The one or more light detectors are optically coupled to the output ends of the one or more light pipes. The alarm is operable to transmit a tamper-event-warning signal if an increased light level is detected by at least one detector.