Abstract: A method of automatic permanent virtual circuit connection activation is provided. The method includes detects initiation of communication between a first and a second network element at a first reference point. The method further receives at least one virtual circuit identifier of the first network element and learning at least one virtual circuit identifier of the second network element. In addition, the method creates a translation connection between the first and second network elements.

Abstract: A circuit that uses a bi-directional buffer as follows: First a tri-state output buffer is connected to a functional clock and a bi-directional port is connected to a test clock. The bi-directional buffer is configured to receive control signals to selectively block and unblock the tri-state output port connected to the functional clock. In addition, the bi-directional port connected to a test clock is connected to the internal logic of the device. When the tri-state output buffer connected to the functional clock is blocked, the test clock transmits a clock signal to the internal logic of the device. When the tri-state output buffer connected to the functional clock is unblocked, the functional clock transmits a clock signal to the internal logic of the device.

Abstract: A port isolator apparatus includes an optical isolator circuit that electrically isolates an input circuit from a high-speed output circuit. The input circuit uses a transistor to control the current flow of a data signal into the optical isolator. The optical isolator generates, from the data signal, an output signal that controls the high-speed output circuit in the regeneration of the output signal. The output signal is substantially similar to the input data signal. The input circuit and the optical isolator circuit are coupled to one power and ground circuit while the high-speed output circuit is coupled to a second power and ground circuit that is isolated from the first power and ground circuit.

Abstract: A communication system includes primary and secondary interface cards. A switching circuit allows both of the interface cards to selectively communicate over a medium without inducing reflection. Further, an automatic detection system is provided to allow a management circuit to identify which interface card is coupled as the primary or secondary card.

Abstract: A device apparatus and method are detailed that allow for improved bit error rate (BER) testing, configuration, and operation of a communication device and associated physical communication link, in particular on a HDSL communication device and link. The improved communication device apparatus and method additionally allow for the communication device to utilize an embedded BER tester (BERT) to run commonly utilized BER tests on high speed communication channels (downstream and upstream) associated with the communication device. The device apparatus and method also allow for a BER test to be configured and initiated remotely, with loopback at a remote device and masking of alarm states at the remote device or local device until the BER test is complete.

Abstract: Methods and systems of monitoring voltage input to network elements are provided. One method includes receiving an input voltage for a line-powered network element, applying the input voltage across a primary winding of a flyback power converter during an on-time of a primary switch, and transferring the input voltage from the primary winding to a secondary winding of the flyback power converter during an off-time of the primary switch. The method further includes sensing the voltage of the secondary winding during the on-time of the primary switch; and drawing minimal current from the flyback power converter.

Abstract: A current sharing circuit provides redundant power supplies with current sharing through the use of multiple feedback loops and existing circuit diodes to generate shared load current within predefined load voltage regulation requirements. A method of sharing current allows adjustment of the feedback loops to accommodate characteristics of the circuit.

Abstract: A ring voltage generator uses values stored in random access memory to generate a train of pulses used to drive a voltage waveform to ring a telephone ringer. The values are stored in RAM, and are programmable by a user without requiring a change in the ring voltage generator design.

Abstract: A system for managing and routing one or more data cables is disclosed. This system comprises a telecommunications enclosure and a cable routing station. The telecommunications enclosure has an external surface that houses at least one data cable. The cable routing station is coupled to the external surface of the telecommunications enclosure and is adapted to selectively route one or more of data cables away from the telecommunications enclosure.

Abstract: An input power sharing control circuit is provided. The control circuit includes a plurality of current limiting circuits each circuit adapted to receive power from one of a plurality of independent power sources, a power switching control circuit adapted to receive power from the plurality of independent power sources and provide a variable power output and a load coupled to the output of the power switching control circuit, wherein the value of the load impedance and the value of the voltage of the output power controls the variable power output.

Abstract: The present invention relates to a method and apparatus for testing components in ATM networks utilizing loop-back based ATM layer testing. The method and apparatus utilize interfaces and identifier codes to send and loop-back test cells along portions of virtual channels to test the virtual channels.

Abstract: Testing an oscillator and other electronic devices on a circuit board. One method of the present invention comprises powering the oscillator. Providing test instructions to a microprocessor on the circuit board to place the microprocessor in a test mode. Receiving a clock signal from the oscillator at a multiplexer in a field programmable gate array. Receiving operating instructions at the multiplexer from the microprocessor. Multiplexing the clock signal to an external access port with the multiplexer in response to the operating instructions and measuring the frequency of the clock signal at the external access port.

Abstract: Resistance in parallel with inductors in a series leg of the low-pass filter facilitates changing input and output resistance of the filter with little or no change in the reactance of the inductors. Furthermore, the reactance of the capacitors in the shunt legs of the filter will be substantially unaffected. This assists the designer in matching the impedance of the filter in the pass-band while still providing substantial impedance mismatching in the stop-band without substantially affecting the characteristics of the filter. Facilitating impedance matching in the pass-band and impedance mismatching in the stop-band is accomplished without the need for more complex active components. POTS splitters making use of such filters can facilitate impedance matching of line and load termination in a telecommunications system in response to signals within the frequencies of typical analog telephony service while providing impedance mismatching in response to signals within the frequencies of typical xDSL service.

Abstract: A method for controlling fan operation that includes detecting a stopped fan and attempting to start the stopped fan. The method includes attempting to start the stopped fan again after at least one first time interval when the fan does not start. The method includes attempting to start the stopped fan again after at least one second time interval when the fan does not start after a predetermined number of first time intervals, where the at least one second time interval is longer than the first time interval.

Abstract: The present invention relates to a method and apparatus for testing components in ATM networks utilizing loop-back based ATM layer testing. The method and apparatus utilize interfaces and identifier codes to send and loop-back test cells along portions of virtual channels to test the virtual channels.

Abstract: An electronics enclosure is provided. The enclosure includes a cylindrical body, one or more modular card cages adapted to receive one or more electronic circuit cards. The one or more modular card cages including an outer frame member in direct physical and thermal contact with an inner wall of the cylindrical body, an inner frame member, one or more support members coupled between the outer frame member and the inner frame member, and a plurality of electronic device retainers adapted to couple to the modular card cage and hold each of the one or more electronic circuit cards in direct physical and thermal contact with one of the one or more support members. The support members provide an isolated heat dissipation path for heat, produced by each of the one or more electronic circuit cards, to be removed from the enclosure.

Abstract: A housing for circuit cards is provided. The housing has a shell. A thermally conductive liner integral with the shell lines an interior of the shell. A protrusion of the liner extends through the shell and contacts the shell to form a pressure seal between the liner and the shell. A heat sink is disposed on an exterior surface of the shell and is thermally coupled to the protrusion of the liner. A case is disposed within the liner and is thermally coupled to the liner. The case is adapted to receive a plurality of circuit cards so that the plurality of circuit cards is thermally coupled to the case.

Abstract: Cascade low-pass filters are useful in attenuating the xDSL band in a POTS splitter. The design of the low-pass filter is a sixth-order filter having two stages. A first stage includes a fourth-order filter, preferably with a stop-band frequency of approximately 48 kHz. A second stage includes a second-order filter in cascade with the fourth-order filter. For this filter, the stop-band frequency is preferably approximately 29 kHz. The inductance value of the second stage is relatively small in comparison to the inductance values of the first stage. In this manner, improvements in xDSL band attenuation are facilitated with little or no eroding of the voice band performance such as insertion loss, pass-band attenuation and return loss.

Abstract: An input power sharing control circuit is provided. The control circuit includes a plurality of current limiting circuits each circuit adapted to receive power from one of a plurality of independent power sources, a power switching control circuit adapted to receive power from the plurality of independent power sources and provide a variable power output and a load coupled to the output of the power switching control circuit, wherein the value of the load impedance and the value of the voltage of the output power controls the variable power output.

Abstract: A protection circuit for a DSL transceiver unit includes a capacitor connected in series between a first and second portion of a primary winding of a transformer. The first and second portions are coupled to first and second lines, respectively, of a twisted-pair telephone line. A first voltage controlled device is coupled to the first line and a chassis ground. The first voltage controlled device has a first threshold turn-on voltage at which the first voltage controlled device provides a first current path from the first line to chassis ground. A resistive device and a second voltage controlled device are coupled across the capacitor in series. The second voltage controlled device has a second threshold turn-on voltage at which the second voltage controlled device provides a second current path from a first capacitor terminal of the capacitor to a second capacitor terminal of the capacitor. The second threshold turn-on voltage is lower than the first threshold turn-on voltage.