Abstract: A data transmission system having a clock pulse generator 1, a plurality of transmitters each including a plurality of switches 7-1 for inputting data, gate circuits 5-1 receiving the outputs of said plurality of switches through one inputs thereof and temporary memory circuits 6-1 for temporarily storing the outputs of the gate circuits. Scanning circuits 3-1 apply outputs successively in synchronization with the output pulses from the clock pulse generator. The transmitters are interconnected first by a synchronous line S.sub.1 adapted to apply the output pulses of the clock pulse generator to the scanning circuits in the transmitters and secondly by a signal line S.sub.2 connecting the outputs terminals of the gate circuits in the transmitters.

Abstract: A security system for supervising the integrity of a communication line having a supervising apparatus which generates first and second random signals, compares these first and second randomly generated signals to provide a third signal and compares this third signal to a fourth signal, and a transponder, also connected to the line, which compares the first and second randomly generated signals to provide the fourth signal to the communication line. The use of randomly generated signals increases the difficulty of breaching line security such that, when the supervisory apparatus detects a difference between the third and fourth signals, it can provide an appropriate alarm, indication, or control.

Abstract: A plurality of remotely located transponder units each communicate with a central station unit to provide a full array of alarm and status signals to the central station. The transponder units are capable of remotely addressing the central station unit directly, without the need for human intervention at the central station, to alter subscriber opening and closing times, passwords, and other system parameters. The transponder also permits defective zones to be shunted either from the central station or locally pending repair, testing and status checks.

Abstract: A centralized monitor and control system includes a plurality of pairs of link lines which connect, in matrix form, a plurality of alarm switches, controlled devices, etc., installed at an alarming terminal end with a plurality of alarm display devices, starting control switches, etc., installed at a receiving end in correspondence with the devices at the terminal end, whereby the display devices adapted to be actuated by the alarm switches or the controlled devices adapted to be actuated by the control devices are operated in response to sequential scanning of the one link lines of the paired link system, thus decreasing the number of the link lines used.The number of the link lines used can be decreased further by effecting the sequential scanning by means of a parallel set of binary coded pulse signals and by connecting the one link line array of the matrix to the alarm switches or the controlled devices and the display devices or the control switches through logical circuits.

Abstract: A conditions monitor circuit for repetitively displaying the condition of a plurality of sensors which recognize different conditions includes a plurality of gates that are divided into groups which specify conditions for their respective sensors. The gates in each group are connected to a particular sensor and there is a clock for sequentially enabling each group of gates. The enabling clock pulse for each group of gates is also connected to a driver circuit to indicate which sensor is being interrogated. The gates in each group are connected to all of the conditions indicating driver circuits through diodes. There are display means connected to the driver circuits for indicating both the particular sensor being scanned and the condition of that sensor.

Abstract: A multiple sensor intrusion alarm system including a central controller which communicates with a plurality of sensors over a single, interconnecting cable. The controller periodically polls each of the sensors, and in response to this polling signal, each sensor returns a signal indicating its status. The absence of a return signal from a particular sensor indicates to the controller that the sensor is malfunctioning or has been tampered with. In a preferred embodiment, the interconnecting cable is a single, two-conductor cable. The controller may also be connected to an alarm panel or remote monitoring station to indicate the presence of an alarm condition.

Abstract: The invention is characterized by the use of electronic scanners independently controlled by a control unit, said scanners cyclically scanning in an autonomous manner the matrices of the contacts which are assigned to them and the control unit cyclically observing the scanners so that when a scanner detects the change in state of a contact, the control unit collects from said scanner the georgraphical data of this contact and causes, during a determined time the display of the number of said contact and possibly signals the category to which it belongs. This signalling can also, according to its category, be accomplished by an acoustic alarm.

Abstract: A "red-alert" end condition digital signal is generated by a transponder system of the present invention formed essentially of MSI's (Medium Scale Integrated Chips) including an oscillator/ripple counter controlling a fixed Gray code logic encoding network in circuit with a driver circuit. The aforementioned system both is initiated by and is in power dependent relationship with a MARK-SPACE interrogation signal and has special utility in digitally monitoring product "overflow" conditions in source/product storage tank networks associated with an oil refinery and/or a chemical complex.

Abstract: An alarm system is disclosed which utilizes the Bell System DATAPHONE (a registered service mark of AT&T Company) Select-A-Station Service equipment to communicate alarm messages from a plurality of protected premises to a central monitoring station. The system includes a plurality of transponder units, one at each of the protected premises, connected to the central monitoring station through the Bell System equipment. The central monitoring station sequentially polls all the transponders. This is accomplished by sequentially setting up connections from the central monitoring station to the transponder units and sending a START tone burst. In response to receipt of a START tone burst, the connected transponder transmits a tone burst reporting the status of the protected premises. This tone burst contains six tone-pairs in defined time slots, each of the tone-pairs identifying the condition of an associated protected zone, AC power status, and whether the protected premises is in its DAY or NIGHT mode.

Abstract: A fire alarm system comprises a plurality of alarms which may be operated via an alarm loop and which, being subject to selective interrogation, each alarm transmits an analog value of a particular characteristic of a fire to a central control, the analog value being tapped from a detector for that characteristic. Each alarm comprises an alarm circuit which has a load resistor which can be connected in parallel to the alarm loop by means of a timing element and which amplifies the current which characterizes the alarm at the instant of interrogation.

Abstract: A fire alarm system has a central control connected to an alarm loop composed of a plurality of fire alarm circuits. Prior to an interrogation of the alarm circuits, the same are disconnected from a supply voltage and supplied by respective capacitors which are charged during connection of a full supply voltage. The individual alarms are subsequently reconnected in the alarm loop in a given sequence by a new voltage change, at a reduced voltage, and each alarm circuit is operable to connect the following alarm circuit to the loop and thus to the line voltage at a time delay corresponding to a measured value of a fire characteristic being monitored by that alarm circuit. In a central analysis device, the relevant alarm circuit address can be derived from the number of preceding increases in line current, and the associated measured value can be derived from the length of the switching delay of the corresponding alarm circuit.

Abstract: A "red-alert" end condition digital signal is generated by a transponder system of the present invention formed essentially of MSI's (Medium Scale Integrated Chips) including an oscillator/ripple counter controlling a fixed Gray code logic encoding network in circuit with a programmed 7-segment decoder/driver. The aforementioned system both is initiated by and is in power dependent relationship with a MARK-SPACE interrogation signal and has special utility in digitally monitoring product "overflow" conditions in source/product storage tank networks associated with an oil refinery and/or chemical complex.

Abstract: A defrost control scans, in a predetermined sequence, the several evaporators of a refrigeration system of the type that is installed in a supermarket and that typically comprises a series of refrigerated food display cases in which the evaporators are mounted. Individual to each evaporator is a defrosting means and a sensing device that operates to put the defrosting means in a standby, ready-to-operate condition whenever it senses that the evaporator is in need of defrost. When the control means reaches, in the scanning sense, an evaporator whose defrosting means has been placed in a ready-to-operate condition, it acts to initiate actual operation of the defrosting means associated with that evaporator. In these circumstances, the scanning of evaporators that follow in the predetermined sequence is temporarily arrested. This assures against overloading of the defrosting means, which may typically be of the "hot gas" type, and hence particularly sensitive to overloading.

Abstract: A detector for smoke and/or selected gases includes a sensor means to which the smoke or gas is applied. The sensor is connected at one terminal to ground, the other terminal going through a current meter, through a control potentiometer to a selected positive DC voltage. A potential detector is connected at a selected point in the potentiometer so as to determine when a selected magnitude of current is flowing through the sensor. The output of the detector goes through an alarm control means, and an alarm, which is sounded whenever the current through the sensor is greater than a selected minimum value. The system also includes a scanning detector system where a plurality of separate sensors are used, each in a separate location.

Abstract: A fault indication signal from a plurality of sensors is used to advance a rotary switch to hunt in search of the terminal at which the signal appears. The terminals of the switch are associated with the corresponding visual fault indications recorded on an endless film mounted on a transport mechanism that is driven in unison with the rotary switch. Upon the occurrence of a second fault, the switch is again triggered to advance in search of the terminal where the second signal appears for successive indication of the second fault location. The switch is automatically stepped to a terminal where a signal indicating the presence of more than one fault appears for permanent indication of the number of such faults. The system can be restarted manually to provide successive indications of the first and second faults to facilitate troubleshooting.

Abstract: A series of signals are derived from respective transducers, fault detection switches, cubicle door interlock switches and the like at appropriate places in an industrial plant or apparatus. The signals are taken to a system which monitors them for the presence of a fault indicating signal or other signal of interest. The system has a series of scanner devices which are controlled by a logic circuit so as to scan the signals one after the other in a repetitive sequence. Since the transducers, switches and such may be linked one with another so that, when one is producing a fault signal, others later in the sequence may also produce such a signal, the logic system operates so that when a fault signal is located, a further scanning sequence is gone through so that there is located the first transducer or switch in the sequence which is producing a fault signal. This transducer or switch is then identified by a numeric or alpha-numeric display device.

Abstract: An alarm system includes: (1) a central station having power generating means and alarm registering means, and (2) a plurality of alarm-producing systems in locations remote from the central system, each electrically connected to the central station through a single pair of conductors, and each including circuitry for producing up to eight separate alarm conditions as the power generating means alternately impresses a first predetermined DC voltage on each pair of conductors simultaneously, then interrupts voltage to all conductors simultaneously, impresses a second predetermined DC voltage only on the first of each pair of conductors simultaneously, and again interrupts voltage to all conductors simultaneously.

Abstract: An indication system for indicating abnormal conditions on an indication drum. A rotary switch having a plurality of stationary contacts connected to a plurality of sensors and a movable contact connected to the indication drum is provided to control the rotation of the indication drum. Receiving an output signal of one of the sensors, the rotary switch rotates together with the indication drum until the movable contact comes into contact with one of the stationary contacts to which the output signal is applied. The indication drum, then, indicates one abnormal condition represented by this output signal. A manually-operated switch is further provided to forcibly rotate the movable contact. When the manually-operated switch is activated, the movable contact is caused to slide over the stationary contacts so as to detect another output signal representing another abnormal condition to be indicated.

Abstract: A terminal for use in a service observing system which collects service observing data at a plurality of geographically dispersed locations and forwards the collected information to a central unit for evaluation. Terminal apparatus at each location scans for incoming service observing data generated from an associated group of service observing circuits which bid for connection to the central unit by placing requests with the service observing terminal. Not all requests are sent to the central unit for evaluation in that the terminal contains internal circuitry which allows control of the service observing bids forwarded to the central unit. Specifically, a memory is provided in the terminal to store the in-service or out-of-service operational status of each of the service observing circuits as determined by the central unit. Update circuitry is provided so that the central unit may change the operational status of selected ones of the service observing units during system operation.

Abstract: A selected predetermined coded alarm is provided indicative of the one of a plurality of leads on which a signal indicative of an alarm condition may appear. If a station coded alarm should be initiated during the transmission of a coded alarm, the coded alarm is immediately terminated and the station coded alarm is given priority and transmitted immediately. Upon completion of the station coded alarm, the coded alarm being transmitted at the time of the receipt of the station coded alarm is transmitted with the new transmission starting at the start of its code irrespective of the status of the transmission at the time of the interruption. Appropriate delays are provided between codes and code elements. The plurality of leads are sequentially scanned, but once a transmitted code is transmitted, it is not retransmitted on a subsequent scan unless a reset signal has been provided. Each transmitted code is repeated a predetermined number of times.

Abstract: This instrument panel comprises at least two small rules or display panels of which one comprises a luminous member for displaying the values supplied from a pulse counter and the other comprises pilot-lamps carrying illuminated symbols corresponding to the magnitudes displayed for the various functions or physical conditions being measured, the device further comprising an electronic assembly consisting of a member adapted to emit periodic signals, of members for converting the signals transmitted from pickups or probes into modulated-frequency pulses, of switching members, of further display apparatus, of apparatus for adjusting the luminous intensity and of apparatus for actuating alarm devices.

Abstract: A measuring system for measuring at a plurality of sampling points, a signal representative of the instantaneous value of a physical parameter, wherein a signal representative of the instantaneous value of the physical parameter being measured is utilized as a reference signal against which the next following signal is compared and so on. The system includes means for passing to an output, signals similar to, or within a predetermined limit of, the immediately preceding signals. A particular application of this measuring system is in the measurement of the temperature of living bodies wherein the changes in temperature are transmitted via a pulse width modulation telemetry system to a receiver incorporating the measuring system. By means of continually up-dating the reference signal it is possible to reject any signal which due to some reason such as radio interference is unacceptable because it varies too much from the previous reading.

Abstract: A plurality of machine tools are linked together by a material handling system which carries workpieces from one machine tool to the next in line along a conveyor. The workpieces are clamped to pallets which are carried on conveyor carts between machine tools and which are shuttled onto the machine tools under the guidance of a material handling computer which controls all of the conveyor carts and pallets in the system. The limit switches which indicate the position of the carts and pallets are wired to the material handling computer over a novel data communication link which uses only two pairs of conductors for each machine tool and each section of the material handling system.