Abstract: In one embodiment, the present invention includes a method of installing an optic fiber in an optics package, wherein the tip of the fiber extends from a sleeve. In one step, a point of the fiber proximate its tip is affixed in a retaining member adjacent a device for communicating signals through the fiber. In a second step, a flexible member is disposed between the retaining member and the sleeve and in axial alignment with the fiber. In a third step, the optic fiber is positioned in the optics package after the step of affixing the fiber in place with the respect to the communicating device. In another embodiment, the present invention includes an optics assembly including an optic fiber having a tip extending from a sleeve and a device for communicating signals through the fiber. The assembly further includes a retaining member for affixing the fiber tip proximate the device for communicating signals through the fiber.

Abstract: A local area network interface for a network element having redundant processors is made by using a pair of connectors for each processor. A delay line is used between pairs of connectors for non-redundant LAN configurations. For redundant LANs, the delay line is not used.

Abstract: The circuit arrangement of the invention presents an oscillator, whose frequency can be linearly varied within a wide control range, without affecting the oscillator's stability. The frequency of a fixed frequency generator (1) is divided to the desired frequency by a frequency divider (2), whose divider ratio can be varied in very small steps, and the resulting jitter is filtered out by a very simple phase control circuit (3). Improved short-term stability and holdover performance are also achieved. The oscillator can be universally used as clock generator in all digital circuit arrangements.

Abstract: A method and system to immediately connect and reswitch connection configurations through a rearrangeable communications matrix that immediately connects an input gate causing rearrangeably blocked condition through the communications matrix to an output gate through a dedicated or extra switching element of the center. With the rearrangeably blocked condition, the method and system select a set of switching elements pairs from the center stage switches to form a plurality of possible connections from the input gates to the output gates that excludes the dedicated switching element. The method and system then determines from the possible connections a minimum rearrangement connection configuration that excludes the dedicated switch and that requires the minimum number of rearrangements of existing communications matrix connections.

Abstract: Working DS3/STS interface cards (18, 46) receive DS3 traffic on incoming DS3 communication lines (12, 42). The interface cards (18, 46) are operable to translate the DS3 signals into STS signals, and to "stuff" them into "A" and "B" clock frames provided to them by an "A" formatter (70) and a "B" formatter (74). These clock frames are then used to transmit data to the "A" formatter (70) and the "B" formatter (74). The DS3/STS interface cards (18,46) inspect incoming STS signals on "A" and "B" buses (82, 84) without having to switch to the inspected signal. Formatters 70 and 74 translate the STS data into formatted data, which eventually are transmitted in optical form on respective optical fibers (150, 190) at clock rates which do not have to be the same. Regeneration input and output ports ( 210, 216, 206, 166) allow the through-communication of telecommunications signals in STS format, obviating the need for down-translation to DS3 format and back-translation to STS format.

Abstract: A top cover and bottom cover made of an electrically conductive material that absorbs and reflects electromagnetic interference (EMI) signals are formed to fit without solder or welding as an EMI shield apparatus over EMI susceptible electronic circuitry on a printed circuit board. The EMI shield apparatus shields the circuitry from EMI while at the same time permitting the communication of desired electromagnetic radio frequency and electrical signals to the circuitry. The EMI shield apparatus includes the use of an electrically conductive layer that is integral to the top and bottom sides of the printed circuit board and which includes conductive channels that penetrate the printed circuit board. The channels prevent EMI from passing through the printed circuit board to the electronic circuitry. Also, the channels receive tangs found both on the top cover and bottom cover. The tangs are positioned to prevent EMI from passing through the top and bottom cover junctures with the conductive layer.

Abstract: A digital communications system with fast facility protection is disclosed. The system includes at least one digital cross-connect which is in bidirectional communication with east and west routes of the network via east and west transmit ports and east and west receive ports. The cross-connect broadcasts a facility over both the east and west routes, and receives the return facility over one of the routes. The cross-connect monitors the error status of the received facility for hard error conditions and excessive error rates, by way of a distributed processor in communication with the port. In the event of an error, the cross-connect blind switches the facility to the inactive port by way of a receive-end switch, according to a first embodiment. According to another embodiment, a head-end switch is performed, thus allowing for improved flexibility for port assignment in the cross-connect.

Abstract: A method and system that include double-clock and double-edge flip-flops that produce a circuit output signal in response to two clock signals that have a first flip-flop that produces a first output signal responsive to a first clock signal and a second flip-flop that produces the second output signal responsive to a second clock signal. The method and system provide a means for producing the circuit output signal in response to exclusively either the first flip-flop producing the first output signal or the second flip-flop producing the second output signal. Applications for the method and system include a double-clock single-data flip-flop circuit, a double-edge, double-data flip-flop circuit, a double-edge, single-data flip-flop circuit and a double-edge J-K flip-flop circuit.

Abstract: A master slave architecture includes a common power supply on a common distribution bus that is used by the master to provide a separate alarm power bus to all of the slaves for powering their individual alarm monitoring circuits for providing the capability to detect an open circuit or loss of power to the slave, and to eliminate hot signals which might otherwise result in CMOS latchup in the slaves; individual slaves having alarm conditions may be individually identified by using an alarm inventory bus.

Abstract: An EMI internal shield made of an electrically conductive material that absorbs and reflects electromagnetic interference (EMI) signals associated to fit with an EMI shield top cover. The EMI internal shield is formed to fit without solder or welding as an EMI shield apparatus over EMI susceptible electronic circuitry on a printed circuit board. The EMI internal shield apparatus not only shields circuitry from EMI sources external to the printed circuit board, but also isolates certain electronic circuits from other electronic circuitry on the printed circuit board. Additionally, the EMI internal shield permits the communication of desired electromagnetic radio frequency and electrical signals to the circuitry inside the shield. The EMI internal shield apparatus includes the use of an electrically conductive layer that is integral to the top of the printed circuit board and which includes conductive channels that penetrate the printed circuit board.

Abstract: High speed telecommunications interface circuitry (10) receives a plurality of incoming telecommunication channels (11), and includes a plurality of working receivers (88) each having an input (83-85) connected to a respective one of the incoming channels (11) . A switching circuit (21) has a plurality of working circuit ports (112-116) each connected to an input (83-85) of a respective one of the working receivers (88). The switching circuit has a spare circuit port (33), and is operable to create a data path between the selected one of the working circuit ports (112-116) and the spare circuit port (33). A spare receiver (88) has an input (128) connected to the spare circuit port (33) of the switching circuit (21). Preferably, a switch card (21) of the switching circuit also includes a plurality of series-connected switches (254-268) which are operable to create a single switching path from a selected one of a plurality of working circuit output ports on the switch card (21) to a spare circuit port (36).

Abstract: In a plurality of working interface circuits (12-19), each circuit has at least one transmitter (86) and at least one receiver (88). A spare interface circuit (35) has at least one transmitter (158) and at least one receiver (154). A switch circuit (21) is coupled to the working interface circuits (12-19) and the spare interface circuit (35) and includes a plurality of switches (110-117; 109; 122, 138, 130, 150) which are operable to create a selected one of at least two data paths. A first of these data paths may be selectively formed from a selected one of the working interface circuits (12-19) to the spare interface circuit (35) to monitor the operation of the selected one of the working interface circuits (12-19) without affecting any communications signal transmitted by that working interface circuit. Another data path may be selectively established from a malfunctioning one of the working interface circuits (12-19) to the spare interface circuit (35).

Abstract: A method and system for determining the minimum number of rearrangements for connecting an input gate to an output gate through a rearrangeably blocked communications matrix represent the communications matrix by a square matrix having a first dimension that represents the input stage switches of the communication matrix, and a second dimension that represents the output stage switches of the communications matrix, and wherein the square matrix has cells each representing an intersection of the first dimension with the second dimension and indicating a possible center stage switch connection through of the communications matrix.

Abstract: An EMI/RFI gasket provides a barrier to EMI and RFI radiation transmission to and from electronic circuits within an electronic system chassis having receptacles that receive electrical connectors and an electrically grounded cover plate that connects the chassis to an electrical ground. The EMI/RFI gasket helps to provide a 360.degree. EMI/RFI barrier for the electronic system chassis. The EMI/RFI gasket is a flexible, electrically-conductive material with sufficient surface area to adhere and electrically connect to the cover plate. The EMI/RFI gasket has a receiving slot that is symmetrical about a longitudinal axis and a latitudinal axis of the gasket plate. A plurality of deflected teeth formed from the gasket plate are positioned around the receiving slot and deflected from the gasket plate to contact the connector at points separated by not greater than a predetermined distance. The predetermined distance is at least in part a function of the expected EMI and RFI radiation wavelengths.

Abstract: In a SONET cross connect, the same physical link is used between the interfaces and the matrix to carry the overhead and the payload. The cross connection function within the matrix may be used to group, concentrate and route the overhead signals between a server and the matrix. The matrix may also be used to transport signals between servers. Overhead may be grouped and transported as payload.

Abstract: In an optical fiber telecommunications network, an optical network unit is provided in the subscriber neighborhood for terminating the optical fiber transmission line and for providing electrical signals over metallic lines to the subscribers. The unit functions to convert the optical signal to an electrical signal and demultiplex the electrical signal to divide out baseband telephony signals from broadband video channels. The electrical signals are further demultiplexed and distributed to line cards serving each subscriber, while the broadband video channels are demultiplexed and provided to subscribers that have requested specific video channels. The system includes a test unit for performing metallic tests and also a means to gather subscriber channel requests to form a video control channel which is transmitted to a remote terminal via a baseband telephony channel.

Abstract: A retainer for removable components that plug into a printed circuit board retains the removable component in an associated sockets on a printed circuit board. The retainer has the form of a clip including a retaining surface that applies a retaining force to the component. The retaining force is largely a spring force that directs the leads into the associated sockets by applying pressure to the top of the component. The retainer further has a positioning surface that positions the retaining surface in association with the component. This is done by the positioning surface engaging the exposed exterior surface of the associated sockets. A connecting surface connects the retaining surface to the positioning surface around the circuit board. In the preferred embodiment, the component is a crystal oscillator that plugs into the printed circuit board. Such crystal oscillators are removable to permit changing the operating frequency of an associated microwave transmission circuit.

Abstract: In fiber telecommunications network where an optical fiber is extended to the subscriber's neighborhood, mechanized loop testing is performed by a test unit located in a network unit in the subscriber's neighborhood. The test unit is responsive to commands from a controller located in the network unit to perform metallic line tests on the lines extending to the subscriber. Test results are stored in a memory associated with the controller in the network unit. Upon receipt of a test request from a central test controller, the controller within the network unit determines if there is sufficient time to perform the test; if so, a new test is performed and the results are conveyed back to the central test controller controller. If sufficient time is not available, the results of the last performed routine test contained in the memory are transmitted back to the central test controller.

Abstract: The invention disclosed includes both a method and apparatus for affixing an optic fiber tip in position with respect to a fiber communications circuit. In one embodiment of the method, a glass positioning member is located proximate the tip of the optic fiber. In another step, the glass positioning member is affixed to the fiber at a first position with respect to the fiber tip. The glass positioning member is also affixed in a second position with respect to the carrier. In a more detailed embodiment, the method of the present invention includes positioning the optic fiber through a channel of the glass positioning member. Heat is applied to the glass positioning member causing it to soften such that its channel collapses around and fuses to the fiber. In still further detail, the fused positioning member/fiber are affixed to a block, and the block is fused to a carrier.

Abstract: A circuit for maintaining a constant voltage across and constant current through an RF cavity includes a RF cavity comprising a common-gate or common-base transistor associated with a current control circuit maintains a constant current flowing through the RF cavity. The current control circuit has a current control BJT associated with the RF cavity and a resistor between the emitter of the current control BJT and the negative source voltage of the RF cavity. The current control BJT and resistor operate as a current source or sink as necessary to maintain a constant current flow through said RF cavity. A constant voltage regulation portion of the circuit maintains a constant voltage across the RF cavity and includes a zener reference diode and a voltage regulation BJT.