Advanced Micro Devices Corporation

Zarlink Semiconductor Limited

Legerity, Inc.

Microsemi Semiconductor (u.s.) Inc.

Merle L Miller

Yan Zhou

Jin Li

Jeffrey Jay Anderson

Dale E Gulick

Firas Najeh Abughazaleh

Vijayakumaran Velayudhan Nair

Walter Stuart Schopfer

Sergio R Ramirez

Imran Baqai

V Vijayakumaran Nair

Michael Edward Stibila

A method and apparatus is provided for ring-trip detection in a line card having an analog-to-digital converter for processing voice signals. The method includes receiving a ringing control signal, transmitting a ringing signal to a subscriber line in response to the ringing control signal, and receiving a portion of the ringing signal from the subscriber line. The method includes converting the portion of the ringing signal to a digital signal using the analog-to-digital converter, and providing a ring-trip indication in response to the digital signal. The apparatus includes first circuitry capable of processing a voice signal, the circuitry including a analog-to-digital converter for processing the voice signal. The apparatus includes a ringing generator, second circuitry, and ring-trip detection logic. The generator is capable providing a ringing signal to a subscriber line in response to receiving a ringing control signal. The second circuitry is capable of delivering the portion of the ringing signal to the analog-to-digital converter of the first circuitry, wherein the analog-to-digital converts the portion of the ringing signal to a digital signal. The ring-trip detection logic is capable of providing a ring-trip indication in response to the digital signal.

Method and apparatus for ringing

A method and apparatus is provided for DC feed control for a line card. The method includes determining if the line card is operating in a current limit region of a DC feed curve and synthesizing a curve in the current limit region. The method further includes determining a loop voltage based on the synthesized curve, and applying the loop voltage to the subscriber line. The apparatus includes logic capable of determining if the line card is operating in a current limit region of a DC feed curve and capable of determining a loop voltage based on a synthesized curve in the current limit region. The apparatus further includes circuitry for applying the loop voltage to the subscriber line.

Method and apparatus for DC feed

A method and apparatus is provided for impedance matching for an apparatus capable of supporting voice and data. The method includes receiving an input signal having at least one of a voice component, data component, and DC component, and filtering at least a portion of the data component and DC component of the input signal to provide a filtered signal. The method further includes adjusting an input impedance of the apparatus to a first preselected value for the voice band in response to the filtered signal and adjusting the input impedance of the first apparatus from the first preselected value to a second preselected value. The method includes adjusting at least one of a magnitude and phase of the filtered signal to adjust the input impedance to a third value.

Method and apparatus for handling voice and data signals

A method and apparatus is provided. The method includes receiving a signal over a connection from a telephonic device, determining if the signal is greater than a first preselected value, and adjusting a transient response time of a host transceiver configured to receive the signal in response to determining that the signal is greater than the first preselected value. The method further includes determining a switch hook state of the telephonic device based on a DC component of the signal. The apparatus includes first logic capable of receiving a signal over a connection from a telephonic device, second logic capable of determining if the signal is greater than a first preselected value, and third logic configured to receive the signal, the third logic being capable of adjusting a transient response of the apparatus configured to receive the signal in response to determining that the signal is greater than the first preselected value. The apparatus further includes fourth logic capable of determining a switch hook state of the telephonic based on a DC component of the signal.

Method and apparatus for switch hook detection

A system and method for providing software-implemented, programmable testing of telephone subscriber line power conditions. The system detects subscriber line faults including resistive faults and foreign voltages on a telephone subscriber line. A user interface is provided to enter user-programmable threshold values corresponding to subscriber line fault conditions. A fault threshold memory is coupled to the user interface to store the generated threshold values. A processing unit is configured and arranged to compare signal attributes on the telephone subscriber line to the generated threshold values stored in the fault threshold memory, and is further configured and arranged to identify an occurrence of a fault corresponding to a predetermined condition introduced onto the telephone subscriber line in response thereto.

System and method for programmable telephone subscriber line test

A gain control arrangement for use in analog-to-digital conversion includes a current generator that generates gain currents as a function of externally applied resistances. The gain currents are sequentially provided to the analog-to-digital converter, enabling the converter to use a single set of externally applied resistances to set differentiated gain factors in each of its channels.

Arrangement and method for controlling gain of analog-to-digital

A system and method for performing diagnostic leakage impedance testing at the subscriber line interface utilizing portions of existing circuitry designated for driving current on the telephone line during normal operation is provided. The diagnostic apparatus is used with a telephone line drive system having a tip-line current-mode amplifier for driving current on the tip line and a ring-line current-mode amplifier for driving current on the ring line during normal operation. A control signal generator generates voltage control signals corresponding to desired subscriber loop voltage characteristics. A voltage sense circuit compares the voltage control signals to actual subscriber loop voltage characteristics resulting from driving the current on the subscriber loop. The current driven onto the subscriber loop is adjusted accordingly. A processor receives an indication of a current level of the current driven onto the subscriber loop, and calculates the leakage impedances on the subscriber loop in response to the current level and the voltage control signals.

Telephone subscriber line diagnostics system and method

An extended chip select reset circuit to generate a reset signal for a device, such as a SLAC, using the chip select line. When the chip select line has been maintained in an active state for at least a predetermined amount of time corresponding to a plurality of data clocks, then a reset signal is generated in order to reset the device. The plurality of data clocks is more than a number of data clocks used to clock in a word of data to the device in a normal mode of operation.

Extended chip select reset apparatus and method

An apparatus for controlling the magnitude of a metering signal used in a communication system includes a high pass filter and a threshold detector. The apparatus is preferably integrated on to a subscriber line audio-processing circuit (SLAC device) which is used on a line card. The device is operable with either 12 kHz of 16 kHz metering signals. The high pass filter preferably includes a shift register and an adder. The level detector preferably includes a shift register, an OR gate and an AND gate. The device preferably is utilized to reduce the echo or reflection caused by the variable impedance of subscriber lines in telephone communication systems.

Metering signal level control circuit

A synchronizer (100, 102, 104, 106) is disclosed operable in a variety of modes. In a Master/Slave mode the synchronizer receives synchronizing clock signals from a device to which it is a 'slave' and generates therefrom synchronizing clock signals to a device to which it is a 'master'. In a Slave/Slave mode the synchronizer receives synchronizing clock signals from two devices to which it is a slave. In this mode the synchronizer can buffer misalignment between the clocks and report their phase difference for corrective action. In a Slave mode, the synchronizer only receives a synchronizing clock signal. A data-routing multiplexer (50, 108, 110) is employed in conjunction with the synchronizer which allows five devices to be connected to the synchronizer. Signals may be routed between any of the devices. Buffers (112, 120, 122) internal to the data-routing multiplexer perform the frame alignment function.

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Austin, TX, United States of America

Merle L Miller