Abstract: A keyboard having N-Key Lockout and Two-Key Rollover Protection is disclosed. Each key switch of the keyboard is assigned a unique time slot in a scan cycle. A key switch actuation results in a logic "1" signal at the input of a shift register which is shifted to the output of the shift register one scan time later. Comparison of the input and output states of the shift register results in a signal which indicates when any key switch has not been actuated during the last scan cycle in order to reset a flip-flop which produces a strobe pulse to external data processing equipment. A modulus 2 counter, and other associated circuitry, inhibits the strobe pulse whenever two key switches are actuated during the same scan cycle.

Abstract: Two orientated magnetic field generating means such as permanent magnets are embedded in a roadway at some distance from each other before a road-sign, said magnets extending on the whole width of the roadway. When a vehicle equipped with a detector crosses said magnets, signals of pseudo-sinusoidal shape are generated. Said signals are applied to elements converting them to calibrated pulses corresponding to the two alternations of the signals. The order of said ulses is checked to validate only pulses appearing in a predetermined order, thus eliminating direction ambiguity. The time separating two pulses is also checked to validate only pairs of pulses comprised in a predetermined time period, thus eliminating interferences from outside. The pairs of pulses are transmitted to at least one time window circuit which is adjusted to a predetermined period of time. Only pairs of pulses appearing within said predetermined period are validated.

Abstract: A room status signaling system is disclosed herein employing a plurality of separate signaling circuits employing the internal telephone wiring so that a separate signaling circuit is provided for each room. The plurality of signaling circuits terminate at a central location or board having an indicator such as a lamp for displaying the status of a room. Each signaling circuit not only includes an indicator lamp in series, but further terminates at its opposite end to a switch located at the room. The switch includes a housing having a slot adapted to receive a coin and a chamber for holding the coin after it has been inserted into and through the slot. The chamber further includes a pair of fixed spaced apart contacts which are insulated from each other and which are mechanically and electrically connected together when the coin is held in the chamber of the holder.

Abstract: A two wire current transmitter providing a current signal representing a parameter measured by a variable reactance transducer along the same two wires that are used to carry excitation power to the circuit. The reactance is measured by a circuit providing a DC signal which controls a current control stage to modify the total current through the two wires. The current control stage has a small number of components and operates on a relatively low voltage.

Abstract: A receiver is disclosed which will receive signals on either one of two closely spaced frequencies. The receiver is of the superheterodyne type and has a local oscillator frequency midway between the two frequencies which the receiver is tuned to. The receiver also includes a tone squelch circuit which mutes the audio unless a tone is received for a period of time.

Abstract: A switch incorporated in a photoelectric intruder detection system provides a simple means for testing the system for a predetermined margin of safety from false alarm producing sources. Upon actuation of the switch, the sensitivity of the system is reduced by a predetermined factor, such factor representing a predesired margin of safety from false alarms. During installation of the system, the switch is actuated to reduce system sensitivity. Upon positioning the system components to provide a desired catch capability, the switch is deactuated, thereby increasing the system sensitivity to a level which provides a margin of safety equal to or greater than the amount of gain reduction effected by the switch.

Abstract: A keyboard apparatus for utilizing equipments, such as electronic musical instruments, computers, and other control and data handling devices, which responds to imposition of a flexible conductive element, such as the operator's finger, on a selected one of a plurality of areas to produce a representation for a character or function corresponding to the selected area. This apparatus consists of a plurality of conductors exposed in different combinations in different areas and a set of logic circuits which discriminately gate the conductors to utilizing equipment when proper combinations are energized. Several conductor arrangements with combinations all sharing one or more unique characteristics are disclosed, along with different logic systems responsive to the characteristics to assure that erroneous information will not be read in. Also disclosed is apparatus to produce an audible sound each time a read in is made and thereby indicate to the operator when the keyboard has responded.

Abstract: A system is disclosed for scanning a keyboard and detecting any depressed key during each scan cycle, and for filtering out any bounce in key contacts closing and opening with a filtering up-down counter that counts up each scan cycle that the same key is found, down each cycle that a different key is also found or that no key is found, and requiring that the filtering counter reach a selected maximum before finding that a key is depressed and that the filtering counter reach zero before starting to filter another key detected to be depressed.

Abstract: System for monitoring spaces by electro-optical means, using optical imaging means (1) capable of detecting objects present in the monitored spaces and beam splitting means (2) for grating resolution of the object images into geometric, mutually complementary components. The imaging and beam splitting means form a correlation imaging sensor system equipped with photoelectric detectors (4,5) for the purpose of separately converging light fluxes corresponding to the image components into analogue electrical signals, and electrical means for measuring the amplitudes and phases of the signals as well as their variations. The correlation sensor system analyzes these values with respect to presence and/or motion of objects within the monitored spaces.

Abstract: An accelerometer telemetry system incorporated in a finger ring is used for monitoring the motor responses of a subject. The system includes an accelerometer, battery and transmitter and provides information to a remote receiver regarding hand movements of a subject wearing the ring, without the constraints of wires. Possible applications include the detection of fatigue from the hand movements of the wearer.

Abstract: A touch operated keyboard comprising an AC driven gas discharge panel display with conductive touch keys located to pick up an AC voltage from the stray field generated by the gas discharge panel is disclosed. A detector detects the drop in AC voltage level of a key due to the proximity of an operator's finger. The touch keys may be deposited upon the surface of the gas panel or upon a separate transparent sheet. The keyboard may be operated to change the information displayed by the gas panel.

Abstract: An electronic keyboard comprises a plurality of depressable keys each one of which comprises a stem normally movable and connected through a spring to a metallic actuator. Each actuator is lodged in a supporting element jutting out from the stem and cooperates with a permanent magnet which retains it in a rest position. Upon the depression of a key, the corresponding spring is loaded and after a predetermined displacement of the key a shoulder of the supporting element cooperates directly with the corresponding actuator disengaging it from the permanent magnet. The actuator is then pushed by the action of the spring to a movable contact of an electronic switch which generates an electrical signal.

Abstract: A logic pulser is disclosed which provides controlled pulses for stimulating a digital logic circuit under test. The pulser is serially programmed, e.g. by means of a manually operated push button switch to generate single pulses, continuous streams of pulses, or bursts of pulses.The pulser may include a visual output indicator such as an LED which flashes in a predetermined sequence to indicate in which mode the pulser is operating.The pulser may also include output circuitry which sets the voltage and automatically adjusts the width of the output pulses to provide appropriate net charge to different types of digital circuitry.

Abstract: Structure for and a method of determining which of a plurality of switches in a series circuit first opens after the circuit has initially been completed, for determining line voltage failure to the series circuit, and for monitoring open switches in the series circuit on start-up, comprising means for and the steps of sensing line voltage failure and the condition of each of the switches and providing sensed signals in accordance therewith, converting the sensed signals into coded output signals representative of the desired information relative to switch and line voltage conditions, and subsequently decoding the coded signals and driving a digital display device therewith to provide a visual readout of line voltage and switch condition. Provision is made for manually decoding the coded signals and providing a display in accordance therewith whereby the first fault in the series circuit prior to the circuit having been completed may be determined.

Abstract: A vertical scale indicator has an index movable relative to a scale for indicating a condition sensed by a signal condition device. The index is supported on a flexible band wound on two drums. One drum is driven directly by a servomotor responsive to signals from the signal condition device and the other drum is driven by the servomotor through spring means for providing relative rotation between the drums to accommodate rotation of the drums through different angles in accordance with the amounts of tape wound on the drums.

Abstract: A keyboard switch system for stenographic machines whereby electrical signals corresponding to key depression may be derived. The switch system is comprised of a plurality of coils each having a coil parameter effecting plunger coaxial therewith and spring loaded to an upper position. The coils are arranged in an assembly so as to be mountable in the stenographic machine with the plunger disposed so as to be contaced and depressed in response to depression of a respective key. Each of the coils form a part of a tuned circuit with plunger position affecting the resonant characteristics so as to create logic levels response to key position.

Abstract: Power lines within a building or other user location are connected through a fuse and a filter to an external power grid that supplies power at the usual 50 Hz or 60 Hz. Communications apparatus such as a central computer and a number of typewriters is connected to the power lines within the building at at least two locations and transmits communications signals over the power lines. The communications signals have a frequency different from the frequency of the electrical power supplied by the external power grid and preferably in the audio range. The filter is tuned to pass the electrical power but substantially to block passage of the communications signals. Two important advantages are that the power lines within the building double as communications lines and that the building presents a purely resistive load to the external power grid, so that the grid has an improved power factor.

Abstract: A meter to be read which has indicator drums and an exterior connector and, on the other hand, a reading apparatus for making a reading of the indications of the drums detachably connected to the connector. A coding unit in the meter comprises for each drum a stepped cam connected to rotate with the corresponding drum. A movable follower is elastically biased against the stepped cam. A smooth cam driven by drive means is capable of maintaining the follower spaced away from the stepped cam outside periods in which the reading apparatus makes said reading. A device detects the movement of the follower.The smooth cam has, in part, a camming surface whose radius increases regularly between values corresponding to the bearing of the follower on end sectors of the stepped cam. A substantially radially extending surface interconnects the maximum and minimum radius parts of the camming surface.

Abstract: A low-power, transient-free, multi-channelled bio-telemetry system utilizes series of C/MOS switches coupled to the data sampling electrodes. Shift register pulses selectively enable the switches to sequentially shift the data sample inputs through nine, switch-controlled channels. The switches have little battery drain and, due to their N and P complimentary arrangement, their gating pulses are effectively cancelled and removed from the system channels. Multiplexing precedes amplification by applying switch outputs to a single, low-power amplifier. A special pulse position modulator employing a ramp generator circuit provides the pulse trains to a keyed transmitter. Other significant improvements including a unique shift register arrangement with a synchronizing interval permit long periods of continuous operation undisturbed by the need for battery changes. The transmitted data is received by a suitable demodulating receiver to produce a recordable output for evaluation and computer analysis.

Abstract: A system for remote reading of indicating devices such as meters and the like, which devices are comprised of a plurality of switch contacts and associated resistance elements. The reading systems senses the closing of one or more of a group of device contacts and does so using only a single pair of sensing lines for each group. Additionally, means is provided for sequencially selecting pairs of lines from a plurality of said pairs of lines, each pair associated with a single group among several assemblies of many groups. The selected pair of sensing lines is routed to an analog-to-digital converter, the output of which is sent to a computing device for processing the data received on the pair of sensing lines.