Abstract: A device arranged to electrically connect and physically attach a hybrid circuit module to a printed wiring card. The device is characterized by a male terminal section arranged to be mounted on a printed wiring card, a compliant section for buffering any flexure or displacement imparted to the hybrid circuit module and a hybrid circuit module accepting section. Additionally, a terminal accepting section is provided disposed to accept the male terminal section of another similar device, allowing the stacking of a plurality of hybrid circuit modules to the printed wiring card.

Abstract: In a data transmission system, apparatus for converting a subrate binary data stream into a binary signal at the line transmission rate comprises means for periodically accepting a date byte from the subrate data stream and; means for expanding the data byte by one additional bit by adding a control bit in the first bit position of the accepting means. The apparatus additionally comprises means for recirculating the expanded data byte through the accepting means a predetermined number of times and means for serially reading out bits of the expanded data byte at the line transmission rate.

Abstract: A transformerless telephone circuit including an integrated circuit pulse dialer and transmit, receive and ringer circuitry employing discrete components. Included in the transmit, receive and dialer circuitry are fixed resistive components, which in combination with each other present a constant impedance to said telephone line.

Abstract: An improved screen printing apparatus for printing conductive, resistive and insulative films to the surfaces of ceramic or glass substrates. The screen printing apparatus is characterized by a carriage having a substrate to be printed resting thereon and a frame member extending about the periphery of the carriage. A mesh screen having an emulsion layer is affixed to the screen and suspended over the substrate. The improvement comprising a pair of force absorbing members attached to the carriage in a space relationship to and on opposite sides of the substrate. A pair of rolling means are attached to opposite sides of a squeegee holder with each rolling means in registration with a respective force absorbing surface. A squeegee extends from a bottom surface of the squeegee holder intermediate the rolling means. As the squeegee holder is drawn across the screen each rolling means travels along a respective force absorbing member.

Abstract: An arrangement for connecting a terminal pin to a printed wiring board conductor via an electrically conductive elastomeric collar positioned about the terminal pin and pressed into a plated through hole connected to the conductor. Ridges are formed on an outer surface of the collar and a tapered lead-in is provided at one end of the collar to permit engagement with and the formation of contact areas between the collar and the plated through hole. The collar additionally may include a drive shoulder at an end opposite the end containing the tapered lead-in. Projections may be formed on the terminal pin which engage cavities formed in the inner wall of the central bore within the collar to retain the terminal pin within a collar. The collar may be of electrically conductive or electrically non-conductive material.

Abstract: A printed wiring board file employing guide tracks of wire construction to engage guide runners of printed wiring board assemblies to be mounted therein. The guide tracks are assembled to lateral positioning members at regular or optionally, predetermined differing spacings and each guide includes a forwardly projecting divergent lead-in area to assist in aligning the board assembly guide runner with the file guide tracks. A pair of depressions are formed in each guide track to engage corresponding projections in the guide runners to retain the board assemblies in their fully inserted position within the file.

Abstract: A printed wiring board file employing printed wiring board guides positionable within the file at a plurality of first predetermined spacings and further positionable at a plurality of second predetermined spacings in increments different from those of said first showings. A tab at one end and a clip at the other end of each printed wiring board guide permit assembly to support members and further permit the removal of same should it become necessary to reposition printed wiring boards within the file.

Abstract: A floating battery feed circuit employs a single primary winding, a pulse width control circuit and a peak detector for providing a controlled current to a subscriber loop. The amplitude of the controlled current is determined by the loop resistance. A comparator circuit has one input connected to the output of a peak detector via a breakdown diode. The second comparator input is connected to a reference voltage. When the voltage from the breakdown diode exceeds a predetermined value the comparator provides an 0 output to indicate an on-hook state. For a peak detector output voltage below said predetermined value, the comparator provides a +5 volt output indicating an off-hook state.

Abstract: A printed wiring board assembly including a printed wiring board including a pair of guide runners attached to an upper and a lower edge thereof. The guide runners include an elongated body, a pair of elongated walls extending the length of and from one side of the body, and a groove formed the length of and on a second opposite side of the body. Projections extend from one of the elongated walls through apertures in the printed wiring board to retain the guide runners in engagement with the board. Protrusions extend into the groove and engage depressions in guide tracks of an associated printed wiring board file to lock the board assembly in its fully inserted position within the file.

Abstract: A guide for use with a vertically oriented printed wiring board supported on a pair of support beams. The guide is of wire construction including guide fingers alternately formed on both sides of the printed wiring board. Attachment members are formed at either end of the guide and optionally may be formed at one or more locations intermediate the ends. The end positioned attachment members are connected to the support beams and the intermediate attachment members may be connected to an associated aligner rod to maintain the guide in a predetermined alignment.

Abstract: An interface circuit for use with a telephone or PABX system or as a device applied to a subscriber's telephone line, that detects ringing voltage signals and either indicates the ringing condition visually or optically couples a detection signal to other annunciator or control devices such as microprocessors. The device conforms to the requirements and limitations for application of a device to the public telephone system. This device does not respond or interfere with voice or data signals nor address signaling.

Abstract: An electret microphone gain regulation circuit employing an active load for use in high quality telephone instruments or handsets where two terminal electret microphones of the current source type are employed. The circuitry provides a heavier load on short loops and a lighter load on long loops to regulate the signal level at its output.

Abstract: A monitor circuit which discriminates between valid and invalid (bouncing) changes in state of monitored sense points. A microprocessor periodically scans a plurality of sense points, logically determines the validity of each sense point during each scan and stores data representing the validity of these sense points in a memory.

Abstract: Under an off-hook condition a pulse width control circuit is periodically turned on by narrow pulses from a clock source. This initiates current flow from a primary dc source via the single primary winding of a transformer, and through power transistors connected in a Darlington configuration. A ramp voltage is developed across an emitter resistor of one of said power transistors and this voltage is feedback to said pulse width control circuit. When the ramp voltage reaches a predetermined value, the pulse width control circuit turns off the power transistors and the energy stored in the transformer is transferred by the collapsing magnetic field into alternating current in the secondary winding. This alternating current is rectified and filtered to provide loop current to the telephone subscriber loop. The voltage reflected from the secondary to the primary is stored in a peak detector circuit which operates to control the length of time during which the ramp voltage builds to its predetermined amplitude.

Abstract: An integrated single-sideband modulator comprises six integrated capacitors C1-C6 and first switch means alternately connecting C1 and C2 as feedback capacitors across a differential input operational amplifier A1. The amplifier has a virtual ground potential on its inverting input terminal for causing it to operate as a voltage source and render the circuit relatively insensitive to parasitic capacitance effects associated with capacitor plates. Second switch means cooperates with A1, C1 and C2 and is responsive to 4-phase clock signals for driving input capacitors C3-C6 so as to convert first and second quadrature-phase input signal voltages into first and second electrical charge flow signals on the inverting input terminal that are a function of products of representations of the first and second voltages in switch state time intervals and associated pulse trains which have a 90.degree. phase difference therebetween and a repetitive pattern such as +1, +1, -1, -1, etc.

Abstract: A first embodiment of an integrable switched capacitor modulator comprises a differential input operational amplifier A1 having a virtual ground potential impressed on its inverting input terminal; capacitors C1, C2 and C3; and switch means operative for alternately (1) charging C1 with an input voltage while connecting C2 and C3 in series with A1 and across it, respectively, for causing it to produce an inverted version of the input voltage, and (2) discharging C2 and C3 while connecting the sample of the input voltage on C1 across A1 for causing it to output a non-inverted sample of the input voltage. The modulated output signal from A1 is preferably bandpass filtered to eliminate baseband spectral components fed through A1 when C2 is connected in series with the input terminal thereof.

Abstract: Apparatus for frequency tuning a waveguide cavity comprises a retainer ring and a knob that are threaded onto a plunger in a spaced apart relationship, with the plunger extending into the cavity. Means is provided for preventing rotation of the plunger and for securely rotatably mounting the knob on the cavity. Set screws in threaded holes extending through the knob protrude into blind holes in the ring for mechanically coupling them together. Lightly threading the screws into the blind holes reduces backlash in the threads so that rotation of the knob, and thus the ring, causes smooth and even movement of the plunger in the cavity. Tightening the screws firmly in the blind holes binds the threads on the knob, ring and plunger for preventing further rotation of the knob and movement of the plunger.