Abstract: A circuit for detecting a failed diode in a multiple diode rectifier bridge detects open or shorted diodes in both multi-phase, half-wave rectification and single or multi-phase full wave rectification arrangements and provides a failure signal for sounding an alarm or tripping the circuit to protect the load or power source as the case may be.

Abstract: The drink service system disclosed in the specification comprises dining and bar areas, a cocktail lounge, a kitchen and an order-taking post separate from and adjacent the dining and bar areas to facilitate the direct delivery of food and drink orders taken by telephone from patrons in the dining area and cocktail lounge in visual communication with the order-taking person (FIGS. 1-4). A combined piano bar-bandstand straddles the bar area and dance floor (FIG. 1). Variably-translucent panels control visual communication with the dining area (FIGS. 1, 8). Each table has its own speaker and volume control for music playing (FIG. 5). Detachable carpet panels permit the movement of telephone and audio cables coupled to the tables (FIG. 6). A phone protection system signals the cutting of any telephone cable (FIG. 7).

Abstract: A key telephone system is provided which comprises: a plurality of key telephones; a key service unit; a plurality of transmission paths each including a first transmission cable for transmitting a voice signal between the key telephone and key service unit, a second transmission cable for transmitting a first control signal from the key telephone to the key service unit, and a third transmission cable for transmitting a second control signal from the key service unit to the key telephone; first, second and third transformers of which the primary windings are connected to the key telephone and the secondary windings to the first, second and third transmission cables; and fourth, fifth and sixth transformers of which the primary windings are coupled with the first, second and third transmission cables, respectively, and the secondary windings to the key service unit.

Abstract: Certain telephone calls cannot be billed properly due to the failure to detect a valid answer signal from the called customer. This disclosure presents an arrangement for detecting irregular calls that are recognized initially by a momentary off-hook signal from the called end of the trunk which is not quickly followed by a release of the trunk. When a momentary off-hook signal is received, the holding time of the trunk is measured. If the holding time exceeds a predetermined threshold a record is made of the lines connected to the trunk.The calls are also categorized by called destination to detect fraudulent calls which are frequently directed to selected destinations.

Abstract: A voltage divider across the interruptor switch contacts provides a measure of the high voltage produced before a spark occurs at the sparkplug. A Zener diode connected to the upper tap of the voltage divider breaks down when this voltage has risen a certain amount as the result of wear of the sparkplug electrodes that widen the gap. The Zener voltage breakdown causes a relay to lock in and to short-circuit a current-limiting resistor in the spark coil primary circuit that allows a higher voltage spark to be produced to assure proper firing of the sparkplugs with the wider gap. Another Zener diode is connected to the lower tap of the voltage divider to sound an alarm and to disable the ignition circuit when the high voltage at which sparks strike in the sparkplug rises to a value for which the insulation of the spark coil and its connection is not designed to withstand.

Abstract: A multi-frequency encoder unit is provided for a mobile radio transmitter which is constructed as a single unitary package comprising a keyboard, a first printed circuit board positioned adjacent to the rear face of the keyboard and which includes a switching circuit for providing connections from the individual keys of the keyboard to a row of connector pins on the first printed circuit board, a second printed circuit board containing the encoder circuit positioned adjacent to the first printed circuit board and electrically connected thereto by way of the connector pins which are received in connector holes in the second printed circuit board, and which includes a relay inside the encoder which causes the transmitter to be energized only as the pushbuttons of the keyboard are operated, and to be de-energized when the pushbuttons are not operated.

Abstract: Disclosed is a switch selector and actuator for use with a telephone repertory dialer and the like where a plurality of contacts are arranged in a row. A rail member is mounted in close proximity to the row of switch contacts and is yieldably biased away from the contacts. A selector member is slidably mounted on the rail member and movable to select a switch contact to be engaged. By depressing the selector member and rail member the contact is engaged.

Abstract: An electronic control circuit for the fuel injectors of an internal combustion engine is disclosed, which comprises a circuitry for detecting certain indicative parameters of the engine working conditions and of the power requirements requested by the engine operator, electronic circuitry means being provided for generating pulse train signals to be compared with the signals corresponding to the detected parameters and circuitry means for effecting a comparison with one of a series of preselected patterns of injector feed (intermittency of feed and duration of each feeding burst) thus enabling a control circuit to enter action so as to adapt the operation of the injectors to the preselected pattern. The operator has thus a comparatively wide choice among a number of typical engine operative situations. Consistent fuel savings can thus be obtained along with a more regular engine run.

Abstract: A latching device for snap engagement with the apertured head of a post wire guide of the type used in communication terminal block installation. The latching device is capable of rotary swinging movement relative to its supporting posts so that a cantilever portion can be moved into overlying relation relative to an adjacent post thereby closing the throat formed by the two posts and serving as a retaining means for wires threaded between the adjacent posts.

Abstract: A control system for the fuel injection mechanism of an internal combustion engine, especially a Diesel engine. In order to adapt the fuel admitted to the engine to exact requirements, a correction is made on the basis of air mass flow rate and fuel temperature. The air mass flow rate is deduced from signals generated by an air temperature sensor and an air pressure sensor while the fuel temperature is taken by a fuel temperature sensor. The two temperature signals are applied to a bridge circuit which feeds a differential amplifier whose output is mixed with the pressure signal. The composite mixed signal is applied to a servo-mechanism to limit the excursion of the fuel control rack of the fuel injection pump. Status indicators generate feedback signals for comparison with set-point signals to provide closed-loop control.

Abstract: An electronic circuit is described for use with an existing fuel injection system in which fuel control pulses are generated on the basis of air flow rate, engine speed and exhaust gas composition. In particular, the existing fuel injection system is assumed to include an exhaust gas sensor with a signal integrator and a throttle position switch which indicates a closed throttle. It is also assumed that the fuel injection system shuts off fuel control pulses when the throttle is closed and engine speed drops below a predetermined value. The present circuit is intended to recognize this fuel shutoff and to set the integrator at an average value irrespective of the "too lean" signal which it receives from the exhaust gas sensor. In this way, upon termination of fuel shutoff, the engine will receive an average mixture rather than a highly enriched one.

Abstract: A circuit which allows a digital network telephone central office to provide coin telephone service without analog-to-digital converters. This circuit controls the transmission of digital data representative of coin telephone control signals. Shift registers are used to store this data for asynchronous transmission to a coin telephone, under control of gating logic circuits which insert one bit periodically in preselected frames of data sent to a coin telephone.

Abstract: A key telephone system for a predetermined number of outside lines comprises only one control lead shared per outside line by cables connected between a key service unit and key telephone sets, respectively. Each telephone set has manually operable keys for supplying a higher voltage to a relevant control lead while an outside line is selected for an answer or a reanswer to a call present thereon and substituting a lower voltage for the higher voltage when it is desired to hold an answered call.

Abstract: A miniature electronic bridge lifter for bridged telephone lines which can be mounted directly on the protector unit in the central office includes an impedance inserted serially in each side of the loop for isolating the nonactive loops from the central office termination and for switching to a low impedance connection whenever a party on one of the bridged line connections goes off-hook. A combination semiconductive and resistive voltage divider detects the voltage across the loop. The resistive component is essentially the only cross-coupling between the telephone lines. When the line voltage falls below a preselected threshold, indicating that the connected party has gone off-hook, a switch is operated to bypass the series impedances and establish a low-loss path to the common line.

Abstract: Communication system interface circuits for bidirectional transmission of signals between terminal sets, each interface circuit comprising a transformer including first winding means coupled through rectifier means and a low-pass filter to a first terminal set and including second winding means having end terminals coupled through diodes to the output of a high frequency inverter and having a center tap coupled through an inductance impedance to a neutral circuit point, a second terminal set being coupled across the inductive impedance. The first terminal set may be connected to a telephone subset with ringing and bias signals being applied in circuit with the inductive impedance. The indictive impedance includes transistor means controlled by an operational amplifier which is controlled from a resistance-capacitance phase-shift means, the impedance being equivalent to that of an inductance and a series resistance.