Abstract: An apparatus for monitoring and testing a twisted pair, particularly useful for an Ethernet network. First and second DC currents alternated with one another are applied to both ends of the line, asynchronously. By monitoring the potential on the line, a determination is made as to the condition of the line. For example, shorted, crossed, improperly terminated or open conditions can be detected. A visual indication of the condition of the line is provided and additionally, the visual indication provides an indication of the traffic level in the network.

Abstract: The present invention is directed to an intrusion detection system having two different types of motion sensors and processing of the signals produced by the motion sensors in a manner to provide a reliable indication of motion within the space being sensed. The intrusion detection system includes a microprocessor and produces an alarm signal if each sensor is activated within a predetermined time period of each other. The unit is also capable of producing what is referred to as a "trouble" signal, based upon a certain number of unconfirmed event signals, i.e. a signal from only one sensor being received, within a predetermined time, indicating that one of the sensors is not operating properly. Once a certain number of unconfirmed event signals are received, the unit operates in one of at least two different default modes whereby a trouble signal or trouble signal and alarm signal are produced by means of a different logic processing step.

Abstract: A detecting and alarming system includes a main alarm circuit provided in a headquarter control center, at least a terminal alarm circuit provided at a local station, and at least a connecting loop conecting the main alarm circuit and each terminal alarm circuit, whereby upon a cutting or a shortcircuiting of the connecting loop between the headquarter control center and the local station, an alarm will be actuated for warning the breaking or shortcircuiting situation.

Abstract: An alarm system includes an electronic central controller or control unit with an internal intrusion sensor. The controller is powered by a single nine volt battery. The system can be expanded by adding auxiliary sensors such as sound discriminators, glass breakage sensors and other low power battery operated sensors. The controller can perform all of the functions normally associated with large A.C. powered systems such as factory adjustable entry/exit and reset delays, entrance monitoring, and controlling of lights and message dialers. The system can be adapted for use in mobile environments.

Abstract: A circuit for detecting the occurrence of an event and for providing an output signal upon the detection of the event includes a sensor for detecting the occurrence of the event. A programmable voltage source is interconnected to the sensor for generating the output signal of a predetermined voltage value. The predetermined voltage value is generated by the programmable voltage source when the programmable voltage source is activated by the sensor. Circuitry is interconnected to the programmable voltage source for preventing identification of the preselected voltage value when the programmable voltage source is not activated by the sensor.

Abstract: A line interruption supervisory device for a fire alarm system is capable of reliably carrying out the line supervision even if the line length is long and/or there is a large number of connected fire detectors. To this end, a terminating capacitor is connected across the terminal of a pair of power/signal lines to which fire detectors are connected. A memory first stores the voltage available on the power/signal lines when the line supervision is requested, immediately followed by the interruption by a cut-off circuit of the power supply to a pair of power/signal lines, and further followed by a comparison of the voltage available on the power/signal lines before the power supply interruption with a line voltage available after a lapse of a predetermined time from the power supply interruption by a line interruption discriminating circuit to determine, according to any difference between these voltages, whether there is an open power/signal line.

Abstract: A fire alarm system includes a receiver unit such as a fire control panel or a repeater having zone lines connected thereto, with various types of fire detectors being connected to the zone line. Supervising power is normally supplied to the zone lines. When the receiver unit receives a fire signal via a zone line from a fire detector, the receiver unit decides from what type of detector the fire signal was transmitted. Types of fire detectors include, for example, a type having as switching means only a mechanical contact for causing said zone line to be in a short-circuited condition, a type having as switching means a switching circuit with a self-holding function, or a type having a response lamp.

Abstract: A multizone intruder detection system comprises a supervisory circuit for verifying, from normal traffic or activity in each of the zones of protection while the system is disarmed, that each of the intrusion sensors is, indeed, functional. In the event one or more sensors does not trip (i.e., sense activity) during the disarm period, the supervisory circuitry inhibits re-arming of the system until the non-tripped senso(s) is "walk-tested" to verify that it is still functional. According to the invention, a programmable timer enables re=arming of the system for a predetermined (preferably brief) time interval immediately following disarmig of the system. This feature offers the edvantage of allowing the user to re-enter the protected premises "after hours" for a brief period of time without having to walk-test all zones of protection before re-arming the system.

Abstract: A multizone intruder detection system comprises a supervisory circuit for verifying, while the system is disarmed, that each of a plurality of intrusion sensors is, indeed, functional. The supervisory circuit inhibits rearming of a disarmed system until it determines that each sensor has successfully operated within a relatively brief time interval just prior to the time an attempt is made to arm the system. A timing circuit, activated by a preliminary arm signal, operates to establish a time window (e.g. 10 minutes) within which the operability of each sensor must be verified (i.e. walk-tested) as a precondition to system arming. Preferably, the timing circuit is reset by each sensor alarm output, whereby the system user is given the full time window to walk-test each sensor. By virtue of the invention, sensor sabotage in a disarmed system can be mitigated.

Abstract: A system is provided for electronically monitoring a group of sensor switches employed at remote locations in security or alarm systems. To monitor the status of individual switches, a matrix of conductors is employed. The matrix has a predetermined number of send conductors by a predetermined number of return conductors. Switch circuits each having a diode connected in series with one of the sensor switches are connected at selected crosspoints of the matrix of conductors between respective send and return conductors. Line selection circuitry responsive to an input signal from a computer selectively permits the supply of a sourcing voltage potential to at least a selected one of the send and return conductors and the supply of a sinking voltage potential to at least a selected one of the remaining send and return conductors.

Abstract: An individual source identification of several signal providers or pick-ups with closable contacts disposed in a twin-wire signal line, in particular for fire detectors in fire alarm systems. The signal pick-up system allows to distinguish actuation of individual sensors separately and apart from a short circuit formation. The fire alarm system also allows connection to automatic sprinkler devices. The fire sensor system is easy to install in that the individual settings of the individual detectors at a construction site are minimized.

Abstract: A temperature sensor located at a region being monitored controls an output switch that in one position when ambient temperature is below a predetermined temperature applies current to only a first loop circuit and in another position when ambient temperature is at or above the predetermined temperature applies current to only a second loop circuit. Currents in the first and second loop circuits are measured by ferrods to determine whether an over-temperature condition at the region monitored has taken place. An alarm circuit connected to outputs of the ferrods generates an alarm signal in response to a negative transaction of current in the first loop circuit or a positive transition of current in the second loop circuit. A failure in either loop circuit accordingly is insufficient to disable the system. A solid state timer periodically opens the second loop circuit to repeat the alarm signal when the second loop circuit is closed until corrective action is taken.

Abstract: A light control apparatus for a vehicle is integrated with headlamp driving relays, a light sensor, a lighting switch which selects a manual mode or an automatic mode, and a control unit which controls the relays in accordance with the light sensor output when the lighting switch selects the automatic mode and turns on or off the headlamps. Two power source systems and two headlamp driving systems are provided. The signal level of a given terminal of the control unit is detected and is input to the microcomputer of the control unit. The microcomputer judges whether or not trouble has occurred by detecting a level difference. An alarm indication is given by a lamp or a buzzer if trouble is detected.

Abstract: An emergency alarm system incorporating both signal generation and voice annunciation capabilities, for installation in a building or other structure. The system includes a standard fire alarm control panel and one or more loud speakers, each speaker having a series blocking capacitor. The panel has conventional supervisory circuitry and sensing/alarm terminals connected therewith, adapted to indicate an alarm condition when conditions warrant, as by signals received on multiple sensor lines that also communicate with the panel. A signal generator and amplifier are arranged to drive the speakers, under alarm conditions. There is provided a circuit-failure indicator including an electrical switch and an electro-responsive actuator device connected with the signal generator. The electro-responsive actuator device, when energized by the signal generator, maintains the switch in a closed-circuit condition.

Abstract: An alarm message generation and broadcast system having supervision including an alarm message generation circuit for generating an alarm message, an output for receiving the alarm message so that the alarm message can be broadcast in response to an alarm event; and a supervision circuit connected to the alarm message generation circuit and responsive to the alarm message for providing a trouble signal when the alarm message is not properly received by the supervision circuit.

Abstract: A remote sensing and indicating system for monitoring and displaying at a central operating location the state or position of a remotely located multiple state element. The multiple state element may be a subsea valve which may be either in an open state or a closed state. The system electronically scans valve position switches, stores data indicating the position and drives lamps to display valve position. Switches at the remotely located valve are selectively closed in response to the state of the valve. The switches are connected to the central location by only two leads.

Abstract: In a microprocessor controlled fire alarm system, a chain of continuous pulses is generated by the microprocessor. The chain of continuous pulses is monitored, and if there is an interruption in the chain of continuous pulses a signal is generated to automatically reset the microprocessor.

Abstract: A device for monitoring the condition of a plurality of remote stations is particularly suited for monitoring the condition of smoke alarms, television antitheft devices and the like in hotels and similar institutions. The device includes a plurality of remote sensors wherein each sensor has a predetermined electrical characteristic, such as a predetermined electrical resistance, and at least one remote sensor is associated with each remote station. A main control unit sequentially measures the electrical characteristic of each of the sensors and then compares the measured electrical characteristic from the sensors with a predetermined value. In the event that the measured value differs from the predetermined value by more than a preset amount, an indicator is activated which advises an operator which sensor, and thus which remote station, has been activated or tampered with thus requiring investigation.

Abstract: The integrity of a two-conductor transmission line, over which d-c energizing voltage is supplied to a series of shunt-connected detectors (such as fire and/or smoke detectors) and which line is terminated by an end-of-line capacitor, is monitored and repetitively tested by periodically and momentarily interrupting the application of the d-c energizing voltage to the transmission line or conductor pair, while at the same time connecting a resistive load across the line's input end to provide a discharge path for the capacitor. If the integrity is normal, meaning that the line is continuous and not open, and has no excessively high series resistance or excessively low shunt resistance, and also meaning that the capacitor is functioning normally and is not deteriorated, the capacitor will discharge very little during each test and will maintain a relatively high voltage across the resistive load.

Abstract: Apparatus for indicating a break in the lines leading from a base station to a monitored instrumentality. Two pairs of wires conduct signals to each contact of a normally open switch-like element in the monitored instrumentality (the closure of which signifies an alarm condition) and return these signals to the base station. The presence or absence of the return signals at predetermined times indicates the condition of the lines and also an alarm condition, even if one of the lines leading to the instrumentality is broken.

Abstract: A digital alarm system of the type having first and second electrically conductive loops connected by an alarm switch. The alarm switch is normally open, but can be closed when an alarm state exists to electrically short one loop to the other. Currents are generated in each of the loops for use in detecting either the closing of the alarm switch or the occurrence of a fault in one of the loops. Resistors are connected to each of the loops for use in detecting the presence or absence of the currents. A first pair of transistor switches alternatingly short-circuit one resistor then the other; and a second pair of transistor switches, synchronized with the first pair, alternatingly short the ends of one loop then those of the other so that when the alarm switch is closed the first pair of transistor switches simultaneously short-circuit both resistors even if a fault occurs anywhere in one of the loops.

Abstract: Fire detection signals are produced with high reliability based upon a quantity smaller than a predetermined quantity from a fire sensing system which detects predetermined standard quantities of combustion products (or physical quantities) such as heat, smoke or light produced by a fire. The system includes a fire sensor connected in parallel with a first semiconductor switching element and a second semiconductor switching element contained in two independent power-supply circuits. The first power-supply circuit contains the first semiconductor switching element which detects a combustion quantity smaller than the standard quantities and which is rendered conductive upon receipt of an early output produced by the fire sensor. The first power supply circuit is connected in parallel with a second power-supply circuit containing the second semi-conductor switching element which detects the standard quantities and which is rendered conductive upon receipt of an alarm output produced by the fire sensor.

Abstract: An alarm system includes a number of self powered indicating elements each with an integral warning device. Each indicating element includes a control circuit which may comprise a transistor switching circuit, transistor oscillator or part of a wheatstone bridge circuit for example. Each of these control circuits is connected via two lines to a common control element at a position remote from the remainder of the control circuit, such element comprising for example a resistor, a battery or a zener diode dependent on the type of control circuit utilized. A switch is also included to provide, on actuation, either a short circuit or open circuit condition between the two lines. Actuation of this switch or tampering with the lines so as to cause a short circuit or open circuit condition to occur will result in operation of the alarm.

Abstract: A circuit for a home safety unit having an emergency light system for providing light in the event of a power failure or when a fire is detected, and a fire detection system for providing an audible alarm indicating the existence of a fire. The circuit includes a battery which is constantly being charged and a low voltage responsive system for indicating a low voltage condition on the battery. A latching system causes the emergency light to be turned off when this low voltage condition is reached, and to remain off until the battery is recharged.

Abstract: An improved a.c. voltage powered warning device for detecting the occurrence of predetermined phenomena, is characterized by battery backup for providing power to the device in the event of interruption of the a.c. voltage. In the disclosed embodiments the warning device is a fire detector having circuitry for supervising the energy level of the backup battery and for providing a warning upon the energy level decreasing to a predetermined value, and for testing a combustion detecting and alarm generating portion of the detector.