Wired Patents (Class 340/533)
  • Patent number: 4926162
    Abstract: A communication line monitor for use in a security or fire detection system of the type including a central alarm station and a communication line. A remote transmitter is coupled to the communication line at the remote end thereof and is assigned one unalterable preassigned address out of 6,561 different addresses. The remote transmitter continuously transmits an eight bit trinary code over the communication line corresponding to its preassigned address. A monitor located at the central alarm station is coupled to the communication line and indicates an alarm condition when the signals received from the remote transmitter fail to correspond to the remote transmitter's preassigned address. The monitor includes a plurality of switches to condition the monitor for identifying the remote transmitter's address. The switches are resettable to any other one of the different addresses.
    Type: Grant
    Filed: October 28, 1988
    Date of Patent: May 15, 1990
    Assignee: Honeywell Inc.
    Inventor: John D. Pickell
  • Patent number: 4893324
    Abstract: A portable fire detector and alarm system includes a rechargeable battery power supply and circuitry that monitors a string of up to forty smoke detectors and signals a telephone auto-dialer and prerecorded message unit whenever an alarm occurs. The distal end of the detector line is fed back to the monitor which then detects any loss of continuity in the lines or input AC power and then signals a trouble signal through the auto-dialer.
    Type: Grant
    Filed: February 16, 1989
    Date of Patent: January 9, 1990
    Inventor: Kenneth M. Scown
  • Patent number: 4881252
    Abstract: A sheltered housing scheme communications system is provided. The system includes a master unit carried by a warden which is able to receive and initiate outside telephone calls. This is accomplished by inserting the master unit into a system cable which controls an auto dialer. The auto dialer is capable of dialing a non-preprogrammed telephone number by operation of the master unit. The master unit also functions to indicate its availability to answer an incoming call to the central control unit.
    Type: Grant
    Filed: June 15, 1988
    Date of Patent: November 14, 1989
    Assignee: Tunstall Telecom Limited
    Inventors: David Jones, David I. Abbott
  • Patent number: 4847595
    Abstract: An intrusion alarm system includes a single transmission line composed of two wires to which a controller and a plurality of detectors are connected. The transmission line transmits electric power as well as detection signals. The controller includes a code transmitter which modulates codes assigned to the respective detectors by using a predetermined carrier wave and transmits them successively with a predetermined time interval, a receiver which receives output signals from the detectors, a display for output signals from the receiver, and a DC power source which is common to the detectors and connected to the line.
    Type: Grant
    Filed: November 20, 1987
    Date of Patent: July 11, 1989
    Assignee: Atsumi Denki Kabushiki Kaisha
    Inventor: Hiromichi Okamoto
  • Patent number: 4843372
    Abstract: Apertured plates are mounted to a bridge structure and cooperate with a mirror system to reflect a laser beam from a laser gun to a laser receiver that is coupled to processing circuitry coupled to a modem that is in turn coupled to a central monitoring station through a telephone line. There are a first pair of aperture plates fixedly secured to one side of a first vertical column and a second vertical column of the bridge and are aligned with each other and a first mirror of the mirror system. A second pair of aperture plates are fixedly secured to another side of the first vertical column and the second vertical column of the bridge and are aligned with each other and a second mirror of the mirror system in order to provide for a forward and reverse passage of the laser beam for detecting the sway and deflection of the bridge.
    Type: Grant
    Filed: January 21, 1988
    Date of Patent: June 27, 1989
    Inventor: Thomas Savino
  • Patent number: 4818997
    Abstract: A remote indicator for use with an existing radar detector wherein a remote unit is located near the existing radar detector for sensing output indications from the radar detector and for providing output signals in response to and indicative of the radar detector output indications, and a console remotely located from the existing radar detector for receiving the remote unit output signals and for providing output indications indicative thereof and in response thereto.
    Type: Grant
    Filed: January 12, 1987
    Date of Patent: April 4, 1989
    Inventor: Steven C. Holmes
  • Patent number: 4796025
    Abstract: A monitor/control communication net with intelligent peripherals, that is, peripherals which are capable of monitoring and/or controlling various devices in accordance with messages received from a central panel cpu and which are also capable of reporting to the central panel the status of one or more devices monitored by the peripheral. Each peripheral is assigned a unique address by which it is polled by the central panel. All communication messages between the central panel and peripherals include a format code which indicates the nature of the message and the length of any data field in the message. Communication time is minimized by permitting the data field to vary in length from one peripheral to another, depending on the number and type of devices being monitored and/or controlled by the peripherals.
    Type: Grant
    Filed: June 4, 1985
    Date of Patent: January 3, 1989
    Assignee: Simplex Time Recorder Co.
    Inventors: Robert W. Farley, Lawrence Kaplan, Daniel J. Rodrigues, Bruce A. Wahler, Charles J. Motyka
  • Patent number: 4737769
    Abstract: An alarm system utilizing existing electrical wiring in conjunction with an alarm box. An alarm signal is manually or automatically generated and is converted to an RF signal which is conducted over the existing electrical wiring to an alarm box. The RF signal is re-converted to an electronic or electrical signal and the alarm signal is visually displayed. Various sensors for sensing the presence of various conditions, such as fire or unauthorized intrusion are removeably or directly affixed to plug receptacles or wall switches. Additionally, the system is connected to circuit protection devices, such as circuit breakers which could be tripped, should a fire conduction be sensed.
    Type: Grant
    Filed: January 3, 1986
    Date of Patent: April 12, 1988
    Inventor: Oscar V. Masot
  • Patent number: 4733223
    Abstract: Apparatus for monitoring the status of and controlling faults at remotely-located components in a single line communications system wherein return data signals from the components are transmitted in the 50 kHz to 200 kHz range, and coupled to the low pass filters commonly used to bypass the active components, thereby permitting the return of signals to the system head-end.
    Type: Grant
    Filed: March 26, 1987
    Date of Patent: March 22, 1988
    Inventor: William C. Gilbert
  • Patent number: 4724426
    Abstract: In self-service stores, pay desks are usually arranged in a row side by side. Anti-theft detectors are often arranged in conjuction with the pay desks, and comprise coil loops generating magnetic fields. The coils are usually fed with a common alternating current. The result of this is that an alarm-generating object at one pay desk can give an alarm at the detectors of an adjacent pay desk. The invention is based on feeding the coil loops in alternate systems with one alternating frequency and the ones in between with a deviating frequency, whereby detection isolation between the systems with the same frequency is achieved.
    Type: Grant
    Filed: March 5, 1986
    Date of Patent: February 9, 1988
    Assignee: Luxor AB
    Inventor: Leif B. Lundberg
  • Patent number: 4717907
    Abstract: A remote parameter monitoring system utilizes a series of half-wave rectifier diodes in combination with a unique overlapping wiring arrangement to provide for location-specific detection of a parameter condition existing at a plurality of spaced locations. In one embodiment of the invention, the system is used for monitoring cracks in helicopter rotor blades and indicating to the crew in the cockpit both the fact of a cracked blade and the specific blade which is cracked. In such embodiment, the system includes a three-phase alternating current transformer whose primary windings are supplied by the helicopter's three-phase alternating current generators and whose secondary windings make up part of the wiring loops between the cockpit and the rotor blades. By controlling currents flowing in opposite directions in the wiring loops, the system allows for blade-specific crack detection of up to six rotor blades by means of only three wires between the rotor blade assembly and the cockpit area.
    Type: Grant
    Filed: March 10, 1986
    Date of Patent: January 5, 1988
    Assignee: Arinc Research Corporation
    Inventor: Stephen R. Troy
  • Patent number: 4712097
    Abstract: Pulse sounds from a measuring device (1) for measuring a radioactive concentration or the like are counted by a preset counter (2). When a count of the preset counter (2) exceeds a predetermined value, the automatic dial device (5-1, 5-2, 5-3) is started to call an owner or the like of a measuring/alarm apparatus. When the owner answers the telephone, an alarm sound is sent from an alarm sound generator (7) onto the telephone line. Output pulse sounds from the measuring device (1) are recorded in a recording device (11) for every predetermined time interval after the alarm sound is sent onto the telephone line. The recorded pulse sounds can be sent to a remote location in response to a remote control signal.
    Type: Grant
    Filed: November 2, 1984
    Date of Patent: December 8, 1987
    Inventor: Kazuo Hashimoto
  • Patent number: 4660023
    Abstract: A supervising system for a group of localities like homes. A local equipment including a transmitter, a receiver and an emergency detector is installed in each locality. Identification signatures are exchanged continuously on a common transmission channel between the equipments by a signalling procedure which is initiated repeatedly. Any equipment may start the procedure and generates thereafter internally all control signals for transmitting its own signature and receiving signatures from the others. All equipments indicate alarm for a locality when its signature is not received correctly. An emergency condition modifies the signature which is transmitted. All equipments have the same system status and can each operate independently of other equipments.
    Type: Grant
    Filed: July 25, 1984
    Date of Patent: April 21, 1987
    Inventors: Rolf A. B. Thern, Hans G. Holmgren
  • Patent number: 4654640
    Abstract: A theft alarm system for use in combination with a digital signal PBX telephone system, includes a plurality of electronic tethers connected to individual pieces of protected equipment. Removal of the tether is automatically detected by a local security monitor which reports the condition to a central security controller via the PBX system. The security controller then provides dial-up reporting of the theft and/or sets an audible alarm at the equipment site.
    Type: Grant
    Filed: December 3, 1985
    Date of Patent: March 31, 1987
    Assignee: United Technologies Corporation
    Inventors: Richard T. Carll, Barry G. Blackaby
  • Patent number: 4635040
    Abstract: A fire detecting system utilizing existing electrical wiring in conjunction with circuit protecting devices provided in a main panel box. Various sensors which sense the presence of a fire condition are directly affixed to plug receptacles or wall switches. These sensors activate a short circuit device or a controlled overload which is utilized to trip a circuit breaker and activate various visual or aural alarms. An alternative embodiment employs an encoded RF signal transmitted over the existing wiring, tripping the circuit breaker by an electromechanical device, thereby activating the aural and visual alarms.
    Type: Grant
    Filed: March 12, 1985
    Date of Patent: January 6, 1987
    Inventor: Oscar V. Masot
  • Patent number: 4616214
    Abstract: A CATV system includes a security system incorporated therein through which a subscriber can automatically or manually transmit various warning or emergency signals to the CATV base station. Apparatus at the base operates to determine the type of warning signal received, and transmits a corresponding confirmation signal to the particular home unit. An indicator on the unit gives a visual indication of the receipt of the corresponding confirmation signal.
    Type: Grant
    Filed: May 25, 1982
    Date of Patent: October 7, 1986
    Assignee: Pioneer Electronic Corp.
    Inventor: Akihiko Naito
  • Patent number: 4531114
    Abstract: An intelligent alarm system includes exit sign units having couplings to a smoke sensor and heat sensor for input information, a speech synthesizer and a strobe light to provide output information and a communication unit to provide communication coupling between exit sign units on a single floor and between interfloor interfaces and a central monitoring unit. The exit sign units provide at least two indications to the occupants. First a strobe light to flash at exits with sufficient intensity to draw attention to the exit and to penetrate smoke in a smoke filled hallway. Second, a speech synthesizer which provides verbal instructions to floor occupants according to the emergency situation. Each exit sign unit is operative independently of the central monitoring unit to set off a local alarm.
    Type: Grant
    Filed: May 6, 1982
    Date of Patent: July 23, 1985
    Assignee: Safety Intelligence Systems
    Inventors: Peter Topol, Michael Slater
  • Patent number: 4518953
    Abstract: A security fence system employs a plurality of very thin, high tensile strength, highly stressed wires arranged relatively close together and between each of which is connected an electrical resistance. A voltage source causes a current to flow through the series-connected wires and resistors. An annealed segment can be formed in each high tensile strength wire and located between the points where each wire is attached to the fence posts, to make stretching of the wires without breaking them impossible. A sensing circuit is connected to the fence and includes voltage comparators and potentiometers for providing adjustable triggering levels. The comparators detect when the current flowing in the fence is altered and trigger an alarm if any of the wires are broken, or if any of the wires contact one another. The alarm can be turned off only by normalizing the fence and actuating a reset switch.
    Type: Grant
    Filed: May 31, 1983
    Date of Patent: May 21, 1985
    Inventors: Kent Hunter, Lawrence D. Hunter
  • Patent number: 4494111
    Abstract: A cable TV security system utilizes three radio frequency signals as three data communication channels: one downstream channel and two upstream channels. A headend alarm processor transmits system commands on the downstream channel. A plurality of subscriber alarm units, connected to the cable TV system, transmit messages on the upstream channels to the headend alarm processor. The respective center frequency of both upstream channels is selectable by command on the downstream channel transmitted from the headend. In the event that one subscriber's alarm unit malfunctions whereby a continuous stream of upstream transmission jams one of the upstream channels, the headend alarm processor changes the respective transmitter frequency of the remaining subscriber alarm units to a clear channel frequency. Alternatively, the frequency or frequencies of the malfunctioning unit may be changed. In either case, system security coverage is rapidly restored.
    Type: Grant
    Filed: December 7, 1981
    Date of Patent: January 15, 1985
    Assignee: General Instrument Corporation
    Inventors: Joseph D. Rocci, Stephen E. Crook, Marc Kauffman
  • Patent number: 4485373
    Abstract: An automatic centralized monitoring security system having a plurality of detectors each capable of detecting and advising a malfunction of any given situation of either a routine or emergency nature and a responder associated in circuit with each detector, the arrangement being such that during normal operation the circuit is in dynamic equilibrium, and that upon a malfunction occurring to influence one or more detectors in the circuit an imbalance is created adapted to give rise to an alarm situation.
    Type: Grant
    Filed: November 17, 1982
    Date of Patent: November 27, 1984
    Assignee: I. E. I (Australia) Proprietary Limited
    Inventor: Martin T. Cole
  • Patent number: 4477799
    Abstract: A cable TV security system utilizes three radio frequency signals as three data communication channels: one downstream channel and two upstream channels. The system includes a plurality of individual subscriber security units which transmit respective alarm messages on an upstream alarm channel essentially when an alarm condition is first detected. If two or more subscriber units attempt to transmit simultaneous alarm messages on the alarm channel, the resulting collision causes a garbled alarm message to be received at the headend. The present invention provides respective apparatus in each subscriber's security unit for responding to two unique headend search commands for identifying the respective addresses of the subscriber unit or units which originated the garbled alarm messages.
    Type: Grant
    Filed: December 7, 1981
    Date of Patent: October 16, 1984
    Assignee: General Instrument Corporation
    Inventors: Joseph D. Rocci, Stephen E. Crook
  • Patent number: 4477800
    Abstract: A cable TV security system utilizes three radio frequency signals as three data communication channels. One downstream channel is provided as a polling channel in available spectrum space in the standard FM band. Two upstream channels are provided in the return portion of the cable spectrum. One of the upstream channels is a polling response channel, and the other is an alarm channel. Subscriber security units transmit on the polling return channel in response to downstream command messages on the polling channel. Alarm conditions are immediately transmitted on the alarm channel so that system response to an alarm condition is fast and substantially independent of the number of subscribers.
    Type: Grant
    Filed: December 7, 1981
    Date of Patent: October 16, 1984
    Assignee: General Instrument Corporation
    Inventor: Thomas E. O'Brien
  • Patent number: 4468664
    Abstract: Zone indication is provided for a facility monitoring and control system by providing the system's sensors and control unit with counters which are simultaneously incremented with clock pulses delivered to the sensors via the multi-wire interconnect cable from the system's control unit. Each sensor output circuit has enabling circuitry connected, as with jumper pins, to a counter output corresponding to a predetermined number or count, and this number or count identifies the sensor. In one embodiment, each sensor output is enabled only during the occurrence of the corresponding count or number from its counter as the counters are incremented through their cycle. When the sensors are used to sense alarm conditions, the sensor sending an alarm signal is identified when an alarm condition signal exists simultaneously with a particular count from the counter at the control unit, with the particular count indicating which sensor is sending the alarm signal.
    Type: Grant
    Filed: January 12, 1982
    Date of Patent: August 28, 1984
    Assignee: American District Telegraph Company
    Inventors: Aaron A. Galvin, John K. Guscott, Martin E. Henderson, Roy L. Harvey
  • Patent number: 4446454
    Abstract: A security system for alerting an intrusion disturbance at an entry point to a residence, or alerting as to other emergency conditions, such as fire is disclosed. In the system, a primary monitoring unit having intrusion detection sensors for placement at entry points to a residence produces an audible acoustic alarm signal upon the occurrence of an intrusion disturbance. The acoustic signal is detected by a secondary monitoring unit which in response transmits an electronic signal through the wiring in the residence. A central monitoring unit receives the transmitted electronic signal and activates an alerting alarm and automatic telephone dialer. The system may further include a portable alarm switch for transmitting a coded radio frequency signal to the central monitoring unit to provide remote activation of an alerting device.
    Type: Grant
    Filed: January 21, 1981
    Date of Patent: May 1, 1984
    Inventor: Ronald E. Pyle
  • Patent number: 4435698
    Abstract: Several arrangement in which several measurement sources (fire alarms) are connected in parallel to a two-wire line. The supply voltage for the measurement sources is simultaneously fed through this line. Here, a measurement is formed by switching a measurement shunt circuit into the two-wire line, to generate measurement pulses, where the switch-in process is controlled by a local pulse generator. Each measurement source is provided with a pulse generator, and all these pulse generators operate at frequencies of the same order of magnitude. A monitoring circuit, at the far end of the two-wire line, is switched through by a pulse generator whose frequency is significantly lower. The pulse duration of the monitoring pulses is no longer than the pulse pauses of the measurement pulses.
    Type: Grant
    Filed: May 13, 1981
    Date of Patent: March 6, 1984
    Assignee: Hekatron GmbH
    Inventor: Werner Klett
  • Patent number: 4409590
    Abstract: A system for providing perimeter security, intra-building communication and control functions, utilizes a pair of single wire loops placed about the periphery of the building, and spaced from one another. At least one facilities unit, for fire detection, appliance control and the like functions, has the powering battery thereof series-connected in one of the perimeter loops, and with that loop being connected to battery trickle-charging circuitry. Each of the unit batteries is bypassed by a capacitive element, selected for the frequency, partly determined by the capacitance between the pair of loops, of an oscillator for detecting proximity of intruders adjacent to the building periphery. The proximity-detection oscillator includes a transformer for coupling a data transceiver to and from the remaining loop, whereby voice and/or digital communications may be modulated upon a magnetic field extending throughout the interior of the building for communications to and from independent units therein.
    Type: Grant
    Filed: September 28, 1981
    Date of Patent: October 11, 1983
    Assignee: General Electric Company
    Inventor: Lewin T. Baker
  • Patent number: 4369438
    Abstract: A sump pump detection and alarm system, comprising electrical circuits and components to detect the existence of three different conditions, namely (1) a high water condition with electric power still available, (2) a high water condition when electrical power has failed, and (3) a failure of electrical power to the sump pump even though there is no high water level at the time, and to energize an alarm when detected to indicate which of the three conditions exists. The invention includes remote alarm stations, and in addition connections to the on-premises telephone line to produce a busy signal or other signal when such number is dialed in the event one of the three sump pump conditions exists, plus connections to a radio transmitter to transmit a radio signal when one of the said conditions exist.
    Type: Grant
    Filed: May 13, 1980
    Date of Patent: January 18, 1983
    Inventor: Joseph R. Wilhelmi
  • Patent number: 4361833
    Abstract: A multi-sensor alarm system and method of protecting a premises include at least one sensor circuit and an alarm circuit which together establish a two-wire closed loop electrical circuit path in which a wide variety of alarm sensors are accommodated. The sensors include two-contact configurations which are normally-closed or normally-open, as well as multiple-contact configurations which are characterized by both normally-closed and normally-open contacts. Each sensor differently changes the electrical parameters of the circuit path; and the alarm circuit includes a transistor which senses each parameter change, and a timer which generates an alarm signal whenever any of the sensors is actuated. Opening or closing the circuit path at any point therein will cause the alarm signal to be generated. A status indicator constantly monitors and supervises the status of the sensors in the circuit path.
    Type: Grant
    Filed: March 25, 1980
    Date of Patent: November 30, 1982
    Assignee: Monitran International, Inc.
    Inventor: Richard P. Allgood
  • Patent number: 4356474
    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.
    Type: Grant
    Filed: March 6, 1981
    Date of Patent: October 26, 1982
    Assignee: Contronic Controls Limited
    Inventors: Peter Humphries, Paul Aeberli
  • Patent number: 4329681
    Abstract: An adjustable tamper sensor system for bolts and screws, which connect a non-conductive base and cover, provides a secure housing. An electrically conductive wire and a resistive element in the cover are coupled to the screws and to a resistive bridge alarm circuit. The resistive element in the sensor cover maintains a balanced circuit, and is shunted by any object with less electrical resistance, causing an alarm to report. If an attempt is made to saw through a bolt securing the cover, the conductive wire will be severed or shorted, activating the alarm. The tamper sensor may actually comprise the housing to form a condition responsive detector.In a more simple embodiment, the tamper sensor may protectively conceal any bolt or screw attached to any object.
    Type: Grant
    Filed: September 18, 1980
    Date of Patent: May 11, 1982
    Inventor: Zane W. Parsons
  • Patent number: 4319229
    Abstract: A system for detecting a fire emergency condition employs three separate and diverse sensors; a heat detector, a smoke detector, and an infrared radiation detector. Either or all of these detectors can activate the alarm. Additionally, the infrared radiation detector can be used to control the energization of the room's artificial illumination means. All sensors are mounted in a common housing and a mirror or lens arrangement is provided to focus the infrared radiation upon the appropriate detector.
    Type: Grant
    Filed: June 9, 1980
    Date of Patent: March 9, 1982
    Assignee: Firecom, Inc.
    Inventor: Gabriel Kirkor
  • Patent number: 4310835
    Abstract: Security equipment comprises a plurality of normally-open or normally-closed switch contacts connected in a loop circuit to a central control circuit. Each pair of switch contacts has a respective resistor connected in parallel therewith and the control circuit is operable to detect changes in resistance due, for example, to an intruder operating one of the switches.
    Type: Grant
    Filed: February 11, 1980
    Date of Patent: January 12, 1982
    Assignee: Donald Arthur Arnold
    Inventor: Philip C. Sefton
  • Patent number: 4305070
    Abstract: Alarm circuitry in a static structure, e.g., a home, is connectable by plug and socket means to alarm circuitry in an automobile. The alarm circuitry in the automobile includes a relay powered from a source in the structure. Opening of alarm switches in the structure or on the automobile disables the relay to close a switch in the automobile horn circuit causing the horn to sound. The relay cannot be re-energized except by operation of re-set switch means located in the structure.
    Type: Grant
    Filed: June 19, 1980
    Date of Patent: December 8, 1981
    Inventor: Herbert L. Samuel
  • Patent number: 4274086
    Abstract: In an alarm system, differently colored leads of the connection cable between the individual distributors are respectively assigned to different current paths according to a random sequence. By providing this association, targeted manipulations at the connection lines of the signal lines are prevented.
    Type: Grant
    Filed: July 2, 1979
    Date of Patent: June 16, 1981
    Assignee: Siemens Aktiengesellschaft
    Inventors: Wolfgang Benckendorff, Hans Kubler
  • Patent number: 4271405
    Abstract: In an alarm control system for protecting a premises, a four conductor bus line leading from a master control station is extended about the interior perimeter of the premises. Sensors positioned near each port of entry to be monitored are connected in parallel relationship to the bus line, as is at least one remote station for manually arming, disarming or activating the system. Each sensor comprises a biased reel carrying line secured to window, door, screen, or the like. Disturbance of a sensor causes a magnetically responsive switch therein to generate a pulse triggering circuitry within the control station to activate the desired alarm device for a predetermined period of time. The system then resets automatically to an armed or ready condition to continue protecting the premises against subsequent intrusions. Preferably, the lines in the sensors are of a thermoplastic material so that the system is also activated by abnormally high temperature in the event of fire.
    Type: Grant
    Filed: January 3, 1978
    Date of Patent: June 2, 1981
    Inventor: Lawrence P. Kitterman
  • Patent number: 4268822
    Abstract: In a system for determining the state of each of a plurality of bi-state devices located remotely from a central station, a group of resonant circuits is connected to a multi-frequency excitation source. A bi-state device is then connected to each resonant circuit. When a particular bi-state device is in one position and its corresponding resonant circuit is being excited by its resonant frequency, a maximum amplitude signal is produced by the resonant circuit. When the bi-state device is in the other position, a lesser amplitude signal is produced. The signal produced by each resonant circuit is fed to detection circuitry and in turn to display circuitry. Thus the state of each of the plurality of bi-state devices is indicated by the display circuitry.The two wire line in addition may serve as a transmission medium for a DC control signal used for controlling a remotely located process control valve or for controlling other final actuators.
    Type: Grant
    Filed: October 18, 1978
    Date of Patent: May 19, 1981
    Assignee: The Foxboro Company
    Inventor: Everett O. Olsen
  • Patent number: 4262283
    Abstract: An alarm system for transmitting alarm information via telephone lines has a plurality of alarm transmitters which are located at subscribers' premises and are adapted to transmit signals indicative of the state of alarms associated with the transmitters along telephone lines to associated receivers. The receivers are located at one or more local exchanges and the receivers at a local exchange are all connected to a local processor. The or each local processor is connected to a central processor which can direct alarm information to one of a number of terminal stations. The local processors continuously scan the outputs of the receivers. When a local processor detects a signal indicative of an alarm condition it transmits a signal coded with the subscriber identity and destination for the alarm information to the central processor which routes the alarm message to the appropriate terminal station.
    Type: Grant
    Filed: March 1, 1978
    Date of Patent: April 14, 1981
    Assignee: The Post Office
    Inventors: Ian C. Chamberlain, Michael J. Barton, Michael H. Howard
  • Patent number: 4258357
    Abstract: The invention consists of applying a signalling condition to a telephone subscriber line to prime a common burglar alarm arrangement provided at the telephone exchange, which arrangement is activated by the removal of the signalling condition from the line by, for example, a burglary detection device. The equipment at the telephone exchange automatically identifies the subscriber line when the signalling condition is removed and activates an event recording alarm equipment in a Police or Security central station, giving a print out of the identity of the subscriber whose premises have been entered. The major advantage of the system is that the cutting of the telephone line causes the tripping of the common alarm equipment.
    Type: Grant
    Filed: June 22, 1979
    Date of Patent: March 24, 1981
    Assignee: Plessey Handel und Investments AG
    Inventor: Leslie J. Browell
  • Patent number: 4257037
    Abstract: A detector and indicator for burglar alarms is provided wherein passive resonators, each tuned to a different frequency, are employed across each of the normally closed series switches of the burglar alarm. An alternating current generator is connected to the series line and tuned progressively to the frequency of each of the passive resonators. If an open circuit occurs across any of the resonators, a detector circuit detects the high impedance which results and actuates an indicator circuit wherein the indicator is selected for the frequency of the resonator of a particular location. Even if a plurality of switches are open, the selection circuit will be activated for the particular locations of the open switches.
    Type: Grant
    Filed: August 15, 1979
    Date of Patent: March 17, 1981
    Assignee: Stellar Systems, Inc.
    Inventor: Ronald W. Mongeon
  • Patent number: 4250484
    Abstract: An alarm system, particularly for use on a train, responsive to a plurality of different alarm conditions for providing outputs for indicating which one or ones of the alarm conditions have been detected. A signal having at least as many frequency components as there are alarm conditions is generated on a transmission line which runs the length of the area over which the conditions are to be detected. Alarm sensing switches are connected to taps of the transmission line, and each switch is connected to a frequency dependent impedance means which is resonant and has a low impedance at one of the frequencies. A filter is provided for each alarm condition to be detected, each such filter having a band pass at one of said resonant frequencies. The presence of an alarm condition causes an alarm switch to change state, which causes one of the impedance means to short circuit a frequency which otherwise would have been passed by one of the filters, thus indicating the presence of an alarm condition.
    Type: Grant
    Filed: November 21, 1977
    Date of Patent: February 10, 1981
    Assignee: Marine Electric Corporation
    Inventor: Harry G. Parke
  • Patent number: 4240078
    Abstract: The supervised conductive loop comprises a plurality of switch elements connected in series with a DC current source. Encoder modules are located in parallel with each of the switch elements. The encoder module comprises an oscillator and an impedance element. When a switch element is opened, the oscillator associated with that switch is energized and places an AC signal on the loop. The frequency of each oscillator uniquely identifies the associated switch element. The impedance element, formed by a resistor and a capacitor, is used both as a filter for the power supply voltage to the oscillator as well as a bandpass filter to permit oscillator signals present on the loop to bypass open switch elements and be detected at any location in the loop. Frequency identifying means are coupled to the loop to permit an indication of which oscillators have been operated.
    Type: Grant
    Filed: June 7, 1978
    Date of Patent: December 16, 1980
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Donald A. Jalonen
  • Patent number: 4238783
    Abstract: An FSK receiver for a single channel analog telemetry system comprises an FSK demodulator, a frequency multiplier, and a frequency-to-voltage converter. An FSK transmitter comprises a voltage-to-frequency converter, a frequency divider, and an FSK tone generator. The principal advantages of this system are greater speed due to faster settling time and reduced errors in accuracy and linearity.
    Type: Grant
    Filed: June 15, 1978
    Date of Patent: December 9, 1980
    Assignee: Acco Industries, Inc.
    Inventor: Roland G. Miller
  • Patent number: 4220949
    Abstract: An electric fence monitor and alarm apparatus and method is provided in which the charge condition of an electric security fence is continuously monitored, and an indication is provided when the charge on the electric fence falls below a pre-determined level. In a preferred embodiment, the charge on the line causes a circuit to be maintained in an energized condition which maintains a relay or other switch means in a first condition preventing the energization of indicator means or alarm means such as sirens, automatic telephone dialers, horns and bells. When the charge on the line falls below a pre-determined level, the relay or other switch means is switched to a second state, after a pre-determined adjustable time delay, to cause the operation of the indicator, thereby alerting the proper personnel to a failure of the charge on the line for any reason. The failure of the charge on the line is often caused by an unauthorized cutting of the line.
    Type: Grant
    Filed: May 3, 1978
    Date of Patent: September 2, 1980
    Assignee: Diversified Manufacturing & Marketing Co., Inc.
    Inventors: George F. Pope, Evelyn O. Childress
  • Patent number: 4207558
    Abstract: Each alarm unit has a sensing circuit which supplies a signal in the presence of a particular problem such as smoke, heat, or equipment failure. The signal energizes an electronic switching device, to couple power to a horn which then produces an alerting tone. The output of the sensing circuit is also coupled by a resistor to electronic switching devices in the other alarm units in the system, so that the occurrence of a problem at one location activates the horn in each alarm unit.
    Type: Grant
    Filed: April 3, 1978
    Date of Patent: June 10, 1980
    Assignee: Pittway Corporation
    Inventor: John J. Kunzer
  • Patent number: 4203096
    Abstract: A time multiplexed sensor monitoring system. A plurality of remote sensor units are connected to a central control unit by a two-wire bus line. Power is supplied to the remote unit sensors by the central control unit. Synchronization of the remote units is provided through momentary interruptions in the power supplied to the remote sensor units. The use of a single two-wire bus line for both application of DC signals to the respective remote sensor units and communication of data from the remote sensor units to the central control unit is facilitated by use of double tone multi-frequency (DTMF) signalling techniques.
    Type: Grant
    Filed: April 6, 1978
    Date of Patent: May 13, 1980
    Assignee: Mallinckrodt, Inc.
    Inventors: Max F. Farley, Edmund L. Dutton
  • Patent number: 4141008
    Abstract: A shielded two-wire cable used to transmit signals from one or more remote receivers to a central signal processing unit in an energy-responsive system is simultaneously used to transmit from the signal processing unit to the receivers (a) a signal proportional to the system noise level, (b) a pulsating signal when the system noise exceeds a level indicative of a desired margin of safety, and/or (c) a steady-state signal when an alarm signal is generated by the signal processing unit.
    Type: Grant
    Filed: December 21, 1977
    Date of Patent: February 20, 1979
    Assignee: Detection Systems, Inc.
    Inventor: Richard L. McMaster
  • Patent number: 4132987
    Abstract: A security system of the type including one or more electrically-continuous closed loops for detecting the presence of an intruder wherein a breach in security indicative of the intrusion is sensed by a change in potential at a point along the line with which the closed loop is electrically connected.
    Type: Grant
    Filed: October 26, 1977
    Date of Patent: January 2, 1979
    Inventor: Richard A. Devereaux