Abstract: A circuit for indicating the status of a telephone line at the CPE end, where the status is either on-hook, ringing, or off-hook is disclosed. The telephone line is the normal two-wire telephone line. First, a transconductance amplifier converts a floating voltage difference between the two-wire telephone line into a current. The current is proportional to the voltage difference. Next, a current to voltage converter converts the current from the transconductance amplifier to a single ended ground referenced voltage. The single ended voltage is proportional to the current from the transconductance amplifier, thus the single ended voltage is proportional to the voltage difference across the two-wire telephone line. A voltage controlled switch is turned ON when the single ended voltage is greater than a predefined value indicating the on-hook status. When the single ended voltage is below the predefined value, the voltage switch is turned OFF indicating the off-hook status.

Abstract: A card file adapter assembly for mounting a plurality printed wiring cards of a smaller size than are normally permitted on an associated electronic equipment mounting rack. The adapter is so constructed in size as to be able to be slid directly into existing mounting hardware of an older type providing mounting space for printed wiring cards of a more reduced size.

Abstract: An enhanced subscriber line interface circuit for a digital switching system which includes a line configuration and protection circuit connection tot he subscriber line and to a thick-film hybrid module. The thick-film hybrid module comprises a high voltage interface circuit and a PCM conversion circuit. The high voltage interface circuit provides power to the subscriber line, converts received analog voice signals transmitted from the subscriber instrument into differential voltage voice signals and detects the subscriber lines status. The PCM conversion circuit is connected to the high voltage interface circuit and is disposed to convert received differential voice signals into PCM digital signals.

Abstract: A digital line card for interfacing a remotely located digital telephone to a central office system by a two-wire connection is disclosed. The digital line card consists of a line interface connected to the two-wire connection. The line interface provides a full duplex transmission link with the remotely located digital telephone over the two-wire connection. A buffer is connected between the line interface and the central office system. The buffer converts data between the line interface and the central office system. The line card further comprising a protocol controller connected to the line interface. The protocol controller performs a packet protocol for communications with the remotely located telephone.

Abstract: In order to accomplish the object of the present invention there is provided a movable standoff for maintaining a distance between a backplane and a shroud. Several receptacles are attached to the front side of the backplane and have pins that pass from the front side of the backplane to the rear side of the backplane. Additionally, the pins pass through the shroud. The movable standoff has an orifice extending from a first end to a second end. The pins of the receptacles pass through the orifice. The first end rests against the back side of the backplane, the shroud rests against the second end. Also, the second end of the movable standoff is smaller than the first end.

Abstract: A hybrid balance and combination codec filter circuit used in a subscriber line interface circuit over which a connection is established between a digital switching network and a subscriber instrument. The hybrid balance and combination codec filter circuit in combination includes a transmit section that converts differential voltage audio signals representing voice transmissions transmitted from the subscriber instrument into Pulse Code Modulated (PCM) encoded digital data, for transmission to the digital switching network. A receive section converts PCM encoded digital data representing voice signals switched through the digital switching network into differential voltage audio signals for transmission to the subscriber instrument. An included hybrid balance and echo cancellation section connected between the transmit section and the receive section reshapes the audio band signals output by the receive section.

Abstract: A ringing signal control circuit used in a Subscriber Line Interface Circuit (SLIC) for connecting a ringing signal bus to a subscriber loop. The ringing signal bus transmits ringing signals along the subscriber loop to a subscriber instrument. The SLIC includes a High Voltage Line Interface (HVLI) circuit connected to the subscriber loop and the ringing signal bus is connected to a ringing generator that provides a source of ringing signals. The ringing signal control circuit comprises a logic interface circuit connected via an address/data bus to a central controller that is arranged to receive ringing connection signals from the central controller and to generate a ringing activation signal. A ring timing circuit receives the ringing activation signal and generates a first and second output signals. The second output signal is transmitted from the ring timing circuit at a specific time interval subsequent to the first output signal.

Abstract: An electrical substrate including a flexible printed circuit mounted on the substrate arranged to provide electrical contact between the flexible printed circuit and circuit contacts on an associated carrier substrate. Portions of the flexible printed circuit extended from the top surface of the electrical substrate to the bottom of the substrate by way of recesses included in the geometry of the electrical substrate. Portions of the flexible printed circuit are folded under the bottom side of the electrical substrate and fastened thereto by some compliant material. Properly positioned, electrical contact is established between the flexible printed circuit and circuit contacts on the carrier substrate.

Abstract: An enhanced high voltage line interface circuit for a digital switching system over which a connection is established between a digital switching system and a subscriber instrument via a subscriber loop. The high voltage line interface circuit includes in combination circuits that provide power to the subscriber loop and convert received analog voice signals transmitted from the subscriber instrument into differential voltage voice signals for subsequent conversion to digital data for use by the digital switching system. Additionally, differential voltage voice signals from the digital switching system are converted to analog voice signals for transmission along the subscriber loop to the subscriber instrument. The high voltage line interface circuit further includes circuits that detect and monitor the subscriber loop status and develop digital logic output signals that are used to report the status of the loop to a digital switching system controller.

Abstract: A drill collar position verifier for use with a drill bit having a drilling depth control collar positioned coaxially thereon. The drill bit is inserted in a cylindrical opening in a plastic block to a depth determined by the position of the collar. Three optical beam sources are positioned at three different predetermined depths in the plastic block. Each optical beam source projects an optical beam across the cylindrical opening and onto a corresponding optical beam detector, unless the drill bit breaks such optical beam projections. The optical beam detectors are connected to logic circuitry which is further connected to LED indicators. If the drill bit protrudes far enough through the plastic block to break the first but not the second and third optical beams, an LED is lit to indicate that the collar is positioned too close to the tip of the drill bit.

Abstract: A tool for separating a printed wiring card under test from an extender card operated in response to insertion of a portion of the tool into a space between the extender card and the card under test and rotation of the tool, facilitating the complete separation of the card under test from the extender card.

Abstract: An over-current verifier circuit used in a Subscriber Line Interface Circuit (SLIC) for validating an over-current condition on a subscriber loop comprising a first counter connected to the SLIC disposed to receive an oversense signal from the SLIC. The first counter begins counting when the oversense signal is received and produces an output signal when the oversense signal is still active after the counter finishes, denoting a dc over-current in the subscriber loop. A timer circuit connected to the SLIC also receives the oversense signal. The timer is arranged to begin counting when the oversense signal is received. A second counter further receives the oversense signal and is advanced by one count on the high to low transition of the oversense signal. The second counter produces an output signal when three counter advances are produced before the timer times out, denoting an ac over-current condition.

Abstract: A substrate mounting device for installing an electrical substrate to a carrier substrate. The substrate mounting device includes a plurality of tabs extending from the perimeter edges of the electrical substrate. First and second substrate guides are mounted to the carrier substrate and each include a lower shelf and a channel extending longitudinally along a substrate guide inner side, from an open end to a top guide. The channel is further defined by a top surface and a plurality of drop guides which in turn form a plurality of slots. Also included are a plurality of flaps formed by molded spring back hinges to facilitate insertion from an upward direction. The electrical substrate is installed by manually placing the electrical substrate onto the flapped areas and then depressing in a downward and forward direction, causing the flaps to move in a downward direction allowing the electrical substrate to encounter top guides which act to urge the electrical substrate downward toward the carrier substrate.

Abstract: An arrangement is disclosed that is added to digital circuit device for providing a way of easily verifying that the device's input and output circuits are operating and connected properly. The arrangement implements a test mode in which a simple exercising sequence is placed on any single input of a defined sequential group of device pins. A resultant output can be observed on the next occurring output and all subsequent outputs of the defined sequential group.

Abstract: A substrate connector guide for installing and electrically connecting an electrical substrate to a carrier substrate. The substrate connector guide includes guide rails mounted on the perimeter edge of the carrier substrate and electrical connectors mounted transversely between the guide rails. First and second substrate guides mounted to the carrier substrate. Each include a channel extending longitudinally along a substrate guide inner side, from an open end. A retention guide assists in maintaining the electrical substrate in proper position after insertion into the carrier substrate guide rails. Electrical connectors are also mounted and electrically connected to the electrical substrate. The electrical substrate is installed by manually inserting the electrical substrate into respective substrate guide open ends and pushing the electrical substrate along the channels. The electrical substrate rests on the carrier substrate and aligns the electrical susbstrate connectors to carrier electrical connectors.

Abstract: An ultraviolet exposure unit for exposing both sides of a printed circuit board to ultraviolet light to cause ultraviolet sensitive materials which have been applied to said printed circuit board to cure. A vertically positioned curing chamber and a printed circuit board carrier system provide vertical orientation and simultaneous application of ultraviolet light to both sides of the printed circuit board when such ultraviolet materials are applied to both sides of the printed circuit board.

Abstract: An improved bi-directional buffer line amplifier is disclosed that provides a high performance analog interface between a Digital Network Interface Circuit (DNIC) and a transmission line. The buffer line amplifier includes a transmit amplifier network including an input connected to a DNIC transmit signal output. The input is arranged to receive transmit signals from the DNIC. A transmit output is connected to a matching network via a selectable gain amplifying circuit. The selectable gain amplifying circuit applies the transmit signals to the matching network in a first or a second gain level. In the first gain level the gain amplifying circuit is removed from the transmit amplifier network and the transmit amplifier network operates as a unity gain amplifier. This allows the buffer line amplifier to work efficiently with transmission line loop lengths from zero to a nominal distance.

Abstract: A method for passing data parameters between a calling program and a called subroutine in a command analysis table of a computer stored data base system is disclosed. The method uses special operating codes written in the native language of the command analysis table, that allow the calling program to put pertinent information about the calling parameters into a temporary storage area. The called program or subroutine, uses a second op-code to collect the stored parameters in the temporary storage area. The pulled parameters are then used to initialize local variables and to load parameter values used by the called subroutine, into associated local registers. Information previously stored in the local registers is saved, and returned to the local registers when the subroutine finishes. Pertinent information for returning back to the calling program is also saved.

Abstract: A printed circuit board handle is disclosed for use with a printed circuit board. The printed circuit board handle includes a flange that extends for the length of the handle and is mounted to the printed circuit board. Two ribs protrude from the side of the flange that is adjacent to the printed circuit board and extend for the length of the handle. The ribs contact the printed circuit board in such a manner as to separate the body of the flange from the printed circuit board and thereby prevent the capillary action that causes entrapment of flux between the flange and the printed circuit board, during the wave soldering process.

Abstract: A first method repairs the conductor traces of a printed circuit board assembly and includes the steps of first locating and isolating a break in an existing conductor trace. After the brake is isolated, an extrusion of a conductive resin material is applied, utilizing an extrusion delivery system. The conductive resin is then cured, hardening the conductive resin. A second method reworks the conductor traces of the printed circuit board assembly. This method severs an existing conductor path between existing electrical elements on the printed circuit board assembly and builds a conductor path to form a new connection. The method includes the steps of severing the conductor trace extending between the leads of a first and a second electrical element. Next, utilizing an extrusion delivery system, a conductive resin is extruded onto the printed circuit board assembly between the lead of the first electrical element and the lead of a third electrical element.