Abstract: A central office line unit (COLU) for a pulse code modulation (PCM) upstream and downstream system in a universal digital loop carrier (UDLC) includes a hybrid circuit for transmitting/receiving an analog signal to/from a switch. An analog-to-digital converter is provided for receiving the analog signal from the hybrid circuit and converting the analog signal to a converted digital signal. A digital transmission circuit transmits/receives a digital signal to/from a remote terminal. A quantizer is provided for evaluating and processing the converted digital signal so that only valid states of the converted digital signal are transmitted to the digital transmission circuit for transmission to the remote terminal. A receiver is used for receiving the digital signal from the digital transmission circuit and for evaluating and processing the digital signal so that only valid states of the digital signal are outputted from the receiver.

Abstract: An electronics enclosure is provided. The enclosure includes a modular card cage adapted to receive one or more electronic circuit cards and a heat sink adapted to protrude through an opening of an enclosure and couple to the modular card cage. The modular card cage and the heat sink provide an isolated heat transfer path for heat, produced by each of the one or more electronic circuit cards, to be removed from the enclosure.

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 system of terminating signals in a telecommunication system is disclosed. In one embodiment a line card comprises functional circuitry, line card connector contacts and a termination resistor. The functional circuitry is used to interface first type ports with second type ports. The line card connector contacts are adapted to be selectively coupled to a backplane of a chassis. The termination resistor is adapted to terminate signal lines when a jumper is coupled across select line card contacts.

Abstract: Apparatus and method for increasing the bandwidth of an optocoupler includes cascode coupling the optocoupler driver transistor with a buffer so as to reduce voltage variations across the driver transistor.

Abstract: A fault associated with a communication medium is analyzed by correlating a first set of information indicative of echo associated with the communication medium with a second set of information indicative of echo. The fault is characterized based on the correlation between the first set of information and the second set of information. The first set of information and the second set of information can include echo canceller coefficients generated by an echo canceller coupled to the communication medium.

Abstract: A fault associated with a communication medium is analyzed by correlating a first set of information indicative of echo associated with the communication medium with a second set of information indicative of echo. The fault is characterized based on the correlation between the first set of information and the second set of information. The first set of information and the second set of information can include echo canceller coefficients generated by an echo canceller coupled to the communication medium.

Abstract: A bit error rate or other performance characteristic of a communication link is monitored using a state machine. The state machine includes at least three states. A sliding window is used in two of the states to determine what state to transition to next. A sum is calculated as a function of the sliding window.

Abstract: A set of edits to data stored in a first database are stored in a second database before submission for rules checking and, if appropriate, storage in the first database. The set of edits are submitted for rules checking as a group.

Abstract: A first process communicates to a second process what data will be used to display a graphical user interface element such as a window or screen. The second process determines if the data used to display the graphical user interface element has changed, and, if the data used to display the graphical user interface element has changed, communicates to a third process that the data used to display the graphical user interface element has changed. Moreover, the third process receives the communication that the data used to display the graphical user interface element has changed, and, in response to the communication that the data used to display the graphical user interface element has changed, displays the graphical user interface element.

Abstract: A graphical user interface element such as a window or a screen is displayed on an output device by sending a single message indicating that the graphical user interface element should be displayed. The message is received, and all the components of the graphical user interface element are displayed. After that, the graphical user interface element can be updated on a component-by-component basis.

Abstract: A method for initiating an action based on a received signature in an input signal is provided. The method includes receiving elements of the input signal, determining when elements of the input signal match corresponding elements in the signature, and initiating a selected action when a selected subset of the elements of the signature match consecutive elements of the input signal.

Abstract: An output of a first data register is coupled to an input of a second data register. The same periodic clock signal clocks both data registers. A controller monitors the clock signal, a first load signal and a read signal. The controller generates a guard band signal using the clock signal and the first load signal. The controller also generates a second guard band signal from the read signal and the clock signal. A second load signal, that is used to load the second data register, is created by performing a logical AND operation on the two guard band signals.

Abstract: An apparatus and method is described that allows for improved correlation of multiple signatures from an input datastream, reducing the complexity and memory size of the correlation operation by utilization of a multiple sequence indexing correlator. The multiple sequence indexing correlator keeps an index into each signature that indicates how many elements have been matched so that only the remaining portion of each signature must be compared to the input data stream. Because of this, no history of the input datastream is kept and only a small portion of each signature is compared at one time. Additionally, the multiple sequence indexing correlator allows for ease of signature modification or addition, pre-execution of functions, signatures with identical substrings but differing lengths to be detected, wild card signature elements, timeouts to determine signature end, null functions, execution hold off for extended signatures, and keystroke detection.

Abstract: A circuit for controlling inrush current to a load is provided. The circuit includes a variable impedance device having a control input. The variable impedance device is coupled between a power supply interface and a load interface. The circuit also includes a control circuit coupled to the control input of the variable impedance device and also coupled to the load interface. The control circuit is adapted to provide a signal at the control input of the variable impedance device which results in a linear increase in applied voltage to the load when the circuit is coupled to an input power source. A resistor is coupled between the first and second terminals of the power supply interface to provide a current discharge path for the control circuit when the circuit is disconnected from the power supply.

Abstract: Testing of analog-to-digital and digital-to-analog converters formed in integrated circuits. In one embodiment, a method of testing an analog-to-digital (A/D) converter comprises applying an analog test signal of a first frequency to an input of the A/D converter. Sampling digital byte samples from an output of the A/D converter at a second sampling frequency and comparing select digital byte samples with each other. When the select digital byte samples match, storing a verify bit in a memory to verify the A/D converter is working. In another embodiment, a method of testing a digital-to-analog (D/A) comprises creating repeating digital byte samples with a logic circuit formed in the integrated circuit. Converting the repeating digital byte samples into an analog test signal with the D/A converter. Comparing the frequency of the analog test signal with the frequency of an expected analog signal to determine if the D/A converter is working.

Abstract: A conditioner unit is wired in parallel with a pair gain test controller used to test a digital loop carrier telephone network. The conditioner unit senses a signal intended to request test results from the pair gain test controller and provides a response signal which indicates that the pair gain test controller performed a successful test, even though the pair gain test controller was not activated. This allows testing of the network without use of a bypass pair or the need to interface the digital loop carrier network with the pair gain test controller.

Abstract: An electronic module having a chassis and a single backplane disposed within the chassis. A plurality of bridge circuit cards is disposed within the chassis and is electrically connected to the single backplane. Each of the plurality of bridge circuit cards is for converting between a local area network protocol and a wide area network protocol. A hub circuit card is disposed within the chassis and is electrically connected to the single backplane so that the hub circuit card is electrically connected to each of the plurality of bridge circuit cards. The single backplane is connectable to each of a plurality of remote units for respectively electrically connecting each of the plurality of remote units to each of the plurality of bridge circuit cards. The single backplane is connectable to a data network for electrically connecting the data network to the hub circuit card.

Abstract: A modular fan unit having a frame receivable within a baffle of a chassis for containing electronic components is provided. Each of a pair of brackets is connected to an end of the frame to form a slot for receiving a wall of the baffle. Moreover, each of the pair of brackets is respectively attachable to a pair of walls of a rack containing the chassis. A fan is attached to the frame so as to align with an aperture located between the pair of brackets and passing through the frame. A controller is attached to the frame and is electrically connected to the fan.

Abstract: A method and system for performing simultaneous tests and avoiding task collisions using a hardware description language includes designating a timeslot for one or more of the simultaneous tests, associating the designated timeslot with one or more of the tasks to be performed in a test, determining if the designated timeslot is available before executing the tasks associated with timeslots and executing the tasks when the designated timeslots become available.