Abstract: A remote data link controller is disclosed for formatting, transmitting and receiving control data over high speed digital data links between the peripheral processors of a plurality of telecommunications switching systems. The remote data link controller includes a microprocessor controlled data link processing circuit which is time shared among all of the digital data links. The remote data link controller processes one transmit and one receive message byte during a reformatting cycle for each digital data link. It stores any intermediate results in a temporary memory than proceeds to service the next digital data link. The remote data link controller fetches intermediate results from the temporary memory, processes the data and stores the next intermediate results in the temporary memory until it has completely serviced all of the digital data links.

Abstract: In a telecommunications switching system, a thick film digital span circuit arrangement is connected between a digital span and a switching network of the switching system. The transmission circuit arrangement converts unipolar switching network data to bipolar data for use by the digital span. The telecommunications switching system provides for duplicated data transmission to the digital span. Duplicated transmission circuits are arranged in an active/standby configuration under CPU control without affecting the overall impedance seen by the digital span.

Abstract: A time-space-time-space-time switching network is composed of a subscriber connected to a remote unit network having a time and space switching stage. The subscriber is then connected to a central office switching system having a time-space-time switching network. Alternatively, the switching network may comprise a subscriber locally connected through the time-space-time switching network of the central office switching system to the space and time stages of the remote switching unit. The remote unit network and the central office network are interconnected by a number of digital spans. In addition, the remote unit and the central office each provide for local to local traffic. That is, traffic which is transmitted only within its own switching network.

Abstract: A frequency disturbance minimization circuit for use in a phase locked loop circuit. A pulse generator eliminates random phase shift, which occurs after a reference clock outage, by synchronizing counted down derivatives of the local and reference clock circuits. A window circuit provides a signal representative of the difference in phase between these local and reference clock circuits. A counter accumulates these phase difference window signals for periodic interrogation by a microprocessor which causes a voltage controlled oscillator to adjust its frequency in the direction necessary to eliminate this phase difference.

Abstract: The method of forming fine line circuit patterns on an insulating coating comprising the steps of applying an insulating coating to a substrate, forming a circuit pattern on the insulating coating surface, filling the circuit pattern with conductive or resistive circuit paste, removing the excess and heating at a temperature for sintering the paste to the coating.

Abstract: A time-space-time switching network (for local to local traffic), a time-space or a space-time switching network portion (for local to remote traffic) is shown for a small remotely located switching system. There are multiple crossovers of PCM data from one information rail to another information rail in this switching system. These two information rails provide for crossover in both the originating and terminating time switching stages for local calls and in only the originating or terminating time switching stages for calls originating or terminating at remotely located switching systems. The information rails remain segregated through the space switching stage of this switching system. The small remotely located switching system is connected to a large host digital switching system via digital spans.

Abstract: A remote switching unit which serves a large digital switching system is shown. The remote switching unit is CPU controlled and interconnects local subscribers to the large switching system. Digital spans connect the remote switching unit to the large switching system. A space switching stage provides for switching local traffic (traffic with the remote switching unit) and remote traffic (traffic from or to the large switching system). In addition, the remote switching unit provides an extended switching capacity with connections to smaller switching units.

Abstract: A device is disclosed for mounting, interconnecting and terminating printed circuits. The invention comprises a frame of insulating material arranged to support, position and confine two printed circuit substrates. A connector molded on one end of the frame extends input/output signals to both substrates. A handle molded on a second end of the frame includes slots through which clips are inserted electrically interconnecting the two substrates. The clips also aid in retaining both substrates to the frame.

Abstract: A method of adding fine line circuits to a thick film microcircuit comprising the steps of: cutting a circuit pattern on a substrate; filling the circuit pattern with a conductive or resistive paste and removing the excess; adding screen printing thick film circuit elements on the substrate surface and over selected portions of the fine line pattern; and heating thereby sintering the paste and thick film elements to the substrate.

Abstract: An electrical apparatus frame mounting a number of electrical assemblies. Access to said electrical assemblies is provided for maintenance purposes, while the assemblies are in operation. Access is provided by a slide out and hinge down arrangement. The electrical assemblies rest on support guides which may be inclined at an angle to the horizontal to provide convection cooling.

Abstract: A low insertion force connection arrangement for establishing a connection between at least two printed wiring boards, each board of the type including at least one printed wiring board terminal. The connection arrangement includes at least one connection spring having a pivot point facing away from the printed wiring boards and located between two actuator engaging areas. The actuator engaging areas face the printed wiring boards and are located between two contacts. The contacts are located at opposite ends of the connection spring facing and in alignment a corresponding terminal of each of the printed wiring boards. A connector body is provided including a plurality of grooves each adapted to receive and retain one of the printed wiring boards in alignment with the other boards, and a plurality of spring receiving cavities, each cavity enclosing a pair of connection springs and including a molded-in fulcrum opposite each spring's pivot point.

Abstract: A low insertion force connection arrangement for establishing a connection between at least two printed wiring boards each of the type including at least one printed wiring board terminal. The connection arrangement includes at least one connection spring including an actuator engaging area located centrally on a side of the spring facing the printed wiring boards and between two pivot points. The pivot points are located on a side of the connection spring facing away from the printed wiring boards and between two contacts. The contacts are located at opposite ends of the connection spring facing and in alignment with corresponding ones of the printed wiring boards terminals.

Abstract: A low insertion force arrangement for establishing a connection to a printed wiring board of the type including at least one printed wiring board terminal. The arrangement includes at least one connection spring including at least one actuator and at least one pivot point. A first embodiment includes an actuator engaging area located centrally on the spring between two pivot points which are located between a contact and a connection spring terminal. A second embodiment includes at least one connection spring including a pivot point centrally located on the spring between an actuator engaging area and a second pivot point both of which are located between a contact and a connection spring terminal. In both embodiments the contact is located at one end of each connection spring in alignment with a corresponding printed wiring board terminal. A connector body is provided including a groove adapted to receive and retain a printed wiring board.

Abstract: A frequency disturbance minimization circuit for use in a phase locked loop circuit. A pulse generator eliminates random phase shift, which occurs after a reference clock outage, by synchronizing counted down derivatives of the local and reference clock circuits. A window circuit provides a signal representative of the difference in phase between these local and reference clock circuits. A counter accumulates these phase difference window signals for periodic interrogation by a microprocessor which causes a voltage controlled oscillator to adjust its frequency in the direction necessary to eliminate this phase difference.

Abstract: A modular Common Channel Interoffice Signaling (CCIS) system is described for use with an electronic switching office. This system provides for minimal impact to the program instructions of the switching office. Virtually all modifiable CCIS program instructions are contained within the CCIS system. Therefore, any feature changes or additions to the CCIS system affect only the CCIS system and not the switching office. In addition, the central processing arrangement of the present CCIS system operates a large number of analog and/or digital transmission devices for CCIS data transfer.

Abstract: A ringing generator testing arrangement for a digital telephone network is shown comprising a zero crossing detector connected to the ring lead of a line circuit under test. The zero crossing detector gates a clock signal into a counter circuit during the negative to positive transition of the ringing generator signal positive half cycle. The counter circuit advances until the next positive to negative transition of the ringing generator signal. At this time, the zero crossing detector cuts off the clock signal and the counter circuit transmits to a central control complex a count representing a measured interval of the ringing generator positive half cycle.

Abstract: A signal transmission system which allows digital signals to be transmitted over twisted pair transmission lines. Master and slave transmission circuits are located at the switching system and terminal ends, respectively, of the transmission line. Both circuits include transmit and receive circuitry. The transmit circuitry includes a summing circuit connected to a constant current generator and the receive circuit includes a differential amplifier connected to a slicer circuit.

Abstract: A Hall effect device test circuit which detects Hall effect device operate and release point failures. A magnetic field circuit, an analog-to-digital conversion circuit, a storage circuit, a comparison circuit and a visual indicator circuit are included. The magnetic field circuit causes the Hall effect device under test to switch between its operate and release states. The analog-to-digital conversion circuit provides a digital value, representative of the intensity of the magnetic field existing at the time of switching. These digital values are then stored in the storage circuit. The comparison circuit compares the stored switching values to predetermined thresholds and causes an appropriate visual pass/fail visual signal to be provided.

Abstract: A display apparatus including a liquid crystal device is disposed to turn on or off in the presence or absence of a control voltage respectively. Information located under the liquid crystal device and normally occulted, becomes visible when the display turns on.