Abstract: In a method and an apparatus for compensation of any variation that occurs in the output power or luminous energy of a LED array used in electrophotographic printing, the time for applying a current to one line of the LED array is optimally divided into a fundamental on-time for constant current application to the individual elements of the LED array and a compensational on-time for selective current application thereto in such a manner that the exposure values on a photosensitive medium become uniform.

Abstract: A telephone line demarcation unit separates the telephone company's property and wiring from those of the user and provides security for the telephone line connections and connectors. Compartments in the unit provide easy access for the user and further provides a selection of different types of connections or equipment that can be utilized. The telephone company terminals and test boards are separately compartmented so that the compartments can be separately sealed with seals to discourage tampering and provide evidence of tampering, and yet the user's portion of the interface box demarcation unit can be easily accessed for connecting a variety of telephone equipment.

Abstract: A method and system for detection of authorized connections to a telephone line where such connections are for the purposes of intercepting voice or data messages. The original or base line impedance would be measured by the system in response to the entry of a special code. The base line is stored in memory and used for subsequent impedance comparisons.

Abstract: Malfunctions in an automatic span line switch due to resonances in high-speed span lines are avoided by interposing signal-free intervals whenever the switch causes a possible phase change to occur in the signal being supplied to the span, preventing the transmission of partial signal pulses, and using quasi-random code and keep-alive signals. Unnecessary phase changes are avoided by verifying the validity of data before allowing it to be put on the span following a data loss; disabling the error detection circuitry for a limited time following a switching operation; and preventing the switching of low-priority span on standby if the failure has been remedied during the standby period.

Abstract: An electronic telephone instrument circuit capable of dialing (address signaling) in either pulse or tone mode. The circuitry permits the placement of a call through a rotary dial only system into a second network that is of a tone only nature. The included circuitry has very high return loss and relatively high level of tone capability and is designed to function with a variety of types of dialer integrated circuits. The present circuitry provides part of its DC current supervision while in the voice mode through the included tone amplifiers circuit thereby minimizing components and reducing current load through the voice network.

Abstract: An apparatus for controlling concentration of a liquid developer in a machine using liquid developer has a developer device for developing an electrostatic latent image by a liquid developer, a tank for containing the liquid developer having an inlet and an outlet, a liquid developer circulating pipe having a supply portion extending from the tank to the inlet and a discharge portion extending from the developer device to the tank, a vacuum pump in the discharge portion of the developer circulating pipe for circulating liquid developer from the tank through the developer device and returning it to the tank, a toner container for containing a concentrated toner liquid, a toner supply pipe having one end connected to the toner container and having the other end connected to the discharge portion of the liquid developer circulating pipe at a location between the developer device and the vacuum pump for supplying concentrated toner liquid to the tank, and a valve in the toner supply pipe for opening and closing t

Abstract: A transistorized current amplifier based on a cascode stage feeding into a composite transistorized output stage. The amplifier employs a constant current source, decoupling (isolation) from the power source and a signal limiting network to lower distortion on high signal input conditions. A two-wire device, the amplifier derives signal and power from a telephone line. Surge protection is provided by a signal limiting network and the inclusion of relatively high value resistors in the circuit.

Abstract: A variable gain amplifier of the logarithmically linear type comprises a divider for dividing a signal applied to the input terminal of the amplifier by a gain control signal. The output of the divider is applied to a first input of a subtractor, the second input of the subtractor being connected to receive the signal applied to the amplifier's input terminal to deliver a signal to the output terminal of the amplifier. The amplifier has an input-to-output characteristic given by (2.sup.n /x)-1 which is approximated to exp{2-x/(2.sup.n-2)}, where x represents the gain control signal.

Abstract: A modular coupler is used to interconnect two modular plug-ended telephone line cords. The coupler includes a first and a second section, each having a base and side walls extending along a length. The first section includes a center wall extending in a width direction between the side walls. A plurality of slots are oriented in a lengthwise direction across the center wall. The second section includes first and second forming walls extending in a width direction and separated by an aperture of sufficient size to receive therebetween the center wall of the first section. A plurality of slots extend in a lengthwise direction across the first and second forming walls and slope inward toward the aperture. A plurality of wires are positioned within the slots of the first and second forming walls. During assembly, the center wall is moved between the first and second forming walls to bend the wires toward the first section while clamping them within the coupler.

Abstract: A protective circuit for use in a subscriber's telephone circuit that includes a repertory memory and includes a battery which provides memory retention current. Circuitry permits the battery to be protected by a series current limiting resistor while maintaining sufficient voltage so that the memory maintains its integrity.

Abstract: An image processor for reproducing a continuous tone image such as a photograph in a black-and-white binary dot image (halftone image) has a linear correction section for converting a sampled digital image signal in a predetermined manner controlled by black and white densities of an original, thereby performing linear conversion between the continuous tone image and the halftone image. The image processor also has another correction section for performing profile emphasis to obtain a clear halftone image.

Abstract: A series regulator responds to an input voltage to produce a constant direct voltage. A resistor is connected at one end to the output of the regulator. A current carrying bus is connected between the other end of the resistor and the input of the inverter whereby current flows through the resistor producing a voltage drop thereacross and thereafter flows into the inverter to supply power thereto. An electronic switch has a closed position at which current on the bus supplied via the resistor is augmented by the current on the bus supplied via the switch. The switch has an open position at which the augmented current is not present on the bus, the switch being placed in the open position whenever a pulse appears in the control voltage and thereafter is placed in the closed position when the pulse disappears and said voltage drop is at least equal to a preselected value.

Abstract: A secretarial answering system for use with a switching system which includes a plurality of subscriber telephone stations each equipped with a buzzer, and a secretarial telephone station equipped with an audible signalling circuit and a plurality of lamp and switch pairs. A line circuit is connected to each subscriber station and monitors its busy, idle and ringing status. A processing unit periodically scans the line circuits to determine changes in the status of the subscriber stations. This processing unit then transmits subscriber station status and identification information to the secretarial telephone station. The secretarial station uses this information to provide visual and audible indications of subscriber station status. In response to operation of the switch associated with a called subscriber station, a directed call pick up or a call transfer message is transmitted by the secretarial station to the switching system.

Abstract: A secretarial telephone station for use with a secretarial answering system and a switching system which includes a plurality of subscriber telephone stations each equipped with a buzzer. The secretarial answering system is connected to the subscriber stations and transmits subscriber station busy, idle and ringing status and line identification information to the secretarial station. The secretarial station includes a lamp and switch pair for each subscriber station, a processing unit and an audible signalling circuit. The processing unit receives this information and causes the lamp associated with each of the subscriber stations to display dark, lit or flashing signals corresponding to the idle, busy and ringing status. The processing unit also causes the audible signalling circuit to provide a ringing tone wherever a lamp is flashed.

Abstract: A recording apparatus wherein a recording medium is fed through the gap between recording electrodes and a rear electrode which are arranged to face each other. A magnetic toner is supplied to the gap between the recording medium and the recording electrodes. While under the state where a magnetic field is formed around the recording electrodes to retain toner particles on the recording electrodes, voltage pulses are selectively applied between the recording electrodes and the rear electrode to thereby transfer the toner particles on the recording electrodes to thereby the recording medium by means of coulomb forces for effecting a recording. The recording electrodes are constituted by recording electrode patterns mounted on a rigid board of an insulating non-magnetic material attached to the periphery of a cylindrical hollow member which houses a rotatable magnet roll.