Abstract: A device comprises an interface for transferring an analog telephony signal. Further, the device comprises a compensation circuit which detects a hum signal in the analog telephony signal, generates a compensation signal opposite in phase with the hum signal, and combines the compensation signal with the analog telephony signal.

Abstract: A method of testing a communication line includes applying a voltage as a function of time on the communication line and measuring at least a first current and a second current flowing via the communication line. The second current is measured at a different point in time than the first current. The method includes deciding whether a given terminal element is connected to the communication line based on the first current and the second current.

Abstract: A device comprises an interface for transferring an analog telephony signal. Further, the device comprises a compensation circuit which detects a hum signal in the analog telephony signal, generates a compensation signal opposite in phase with the hum signal, and combines the compensation signal with the analog telephony signal.

Abstract: Audio processing systems and corresponding methods are disclosed, wherein the audio processing system comprises at least one of an analog portion and a digital portion.

Abstract: A method of testing a communication line includes applying a voltage as a function of time on the communication line. The function includes at least one ramp and at least one plateau. The method includes measuring a current flowing via the communication line, and calculating at least one electrical property of the communication line based on the voltage and the current.

Abstract: A subscriber line interface circuit (SLIC) is herein described. In accordance with one aspect of the present proffered solution, the SLIC includes a first interface circuit operably coupled to a first subscriber loop and a second interface circuit operably coupled to a second subscriber loop. The SLIC further includes a power supply circuit that is coupled to the first and second interface circuits to provide first and second output voltages to the respective interface circuits. The power supply circuit includes a switching power converter that is operably supplied with an input voltage and is configured to provide an intermediate voltage signal at an intermediate circuit node. At least a first and a second output branch are connected to the intermediate circuit node. Each output branch includes an output capacitor that is coupled to the intermediate circuit node and that provides an output voltage signal that depends on the intermediate voltage signal.

Abstract: A system and method for testing a transmission line to a protected system includes measuring voltages between a tip-side node of an overcurrent protection device and the protected system, between a ring-side node of the overcurrent protection device and the protected system, between the tip of the transmission line and the protected system, and between the ring of the transmission line and the protected system. Using the measured voltages, the status of the overcurrent protection device and the overvoltage device may be recognized, and the magnitude of a voltage surge on either of the tip and ring wires may be determined.

Abstract: Embodiments related to line testing are described and depicted. A digital subscriber line testing apparatus comprises a plurality of resistors and a switching device. The switching device comprises first and second signal inputs to couple the switching device to a signal generator output, and a plurality of wire terminals. The switching device is configured to switch the plurality of resistors into a first switching state and a second switching state.

Abstract: A subscriber line interface circuit (SLIC) is herein described. In accordance with one aspect of the present proffered solution, the SLIC includes a first interface circuit operably coupled to a first subscriber loop and a second interface circuit operably coupled to a second subscriber loop. The SLIC further includes a power supply circuit that is coupled to the first and second interface circuits to provide first and second output voltages to the respective interface circuits. The power supply circuit includes a switching power converter that is operably supplied with an input voltage and is configured to provide an intermediate voltage signal at an intermediate circuit node. At least a first and a second output branch are connected to the intermediate circuit node. Each output branch includes an output capacitor that is coupled to the intermediate circuit node and that provides an output voltage signal that depends on the intermediate voltage signal.

Abstract: A subscriber line interface circuit (SLIC) is herein described. In accordance with one aspect of the present proffered solution, the SLIC includes a first interface circuit operably coupled to a first subscriber loop and a second interface circuit operably coupled to a second subscriber loop. The SLIC further includes a power supply circuit that is coupled to the first and second interface circuits to provide first and second output voltages to the respective interface circuits. The power supply circuit includes a switching power converter that is operably supplied with an input voltage and is configured to provide an intermediate voltage signal at an intermediate circuit node. At least a first and a second output branch are connected to the intermediate circuit node. Each output branch includes an output capacitor that is coupled to the intermediate circuit node and that provides an output voltage signal that depends on the intermediate voltage signal.

Abstract: A control device includes a circuit operable to sense an analog input voltage dependent on a line current flowing via a communication line of a terminal generate an analog difference voltage in a constant line current operation based on a difference between the sensed analog input voltage and an analog feedback voltage which depends on an adjustable nominal direct-current value and filter a sequence of control error values from a sequence of digital difference voltage values converted from the generated analog difference voltage. The circuit is further operable to convert a control value generated from the sequence of control error values in the constant line current operation to an analog direct voltage for supplying the terminal and convert the nominal direct-current value into the analog feedback voltage in the constant line current operation.

Abstract: A CODEC circuit for POTS system comprises a digital circuit for outputting a digital control signal having a first bit width, the digital control signal being indicative of a voltage to be applied to a POTS subscriber line pair. Further, the CODEC comprises a noise shaper coupled to an output of the digital circuit for generating a noise-shaped control signal and a digital-to-analog converter coupled to an output of the noise shaper, the input of the digital-to-analog converter having a second bit width being larger than 1 and smaller than the first bit width.

Abstract: A system and method for testing a transmission line to a protected system includes measuring voltages between a tip-side node of an overcurrent protection device and the protected system, between a ring-side node of the overcurrent protection device and the protected system, between the tip of the transmission line and the protected system, and between the ring of the transmission line and the protected system. Using the measured voltages, the status of the overcurrent protection device and the overvoltage device may be recognized, and the magnitude of a voltage surge on either of the tip and ring wires may be determined.

Abstract: A signal generator is disclosed that generates a test signal to be applied to a first and second wire of a subscriber line. The signal generator is configured to generate the test signal at the first and second test signal outputs in a first time section such that a first potential at the first test signal output is changed from a first value to a second value and a second potential at the second test signal output is maintained constant at least during the change of the first potential. The signal generator is further configured to generate the test signal during a second time section such that the first potential at the first output and the second potential at the second output are oscillating with a predetermined frequency.

Abstract: A CODEC circuit for POTS system comprises a digital circuit for outputting a digital control signal having a first bit width, the digital control signal being indicative of a voltage to be applied to a POTS subscriber line pair. Further, the CODEC circuit comprises a noise shaper coupled to an output of the digital circuit for generating a noise-shaped control signal and a digital-to-analog converter coupled to an output of the noise shaper, the input of the digital-to-analog converter having a second bit width being larger than 1 and smaller than the first bit width.

Abstract: A CODEC circuit for POTS system comprises a digital circuit for outputting a digital control signal having a first bit width, the digital control signal being indicative of a voltage to be applied to a POTS subscriber line pair. Further, the CODEC comprises a noise shaper coupled to an output of the digital circuit for generating a noise-shaped control signal and a digital-to-analog converter coupled to an output of the noise shaper, the input of the digital-to-analog converter having a second bit width being larger than 1 and smaller than the first bit width.

Abstract: A control device includes a circuit operable to sense an analogue input voltage dependent on a line current flowing via a communication line of a terminal generate an analogue difference voltage in a constant line current operation based on a difference between the sensed analogue input voltage and an analogue feedback voltage which depends on an adjustable nominal direct-current value and filter a sequence of control error values from a sequence of digital difference voltage values converted from the generated analogue difference voltage. The circuit is further operable to convert a control value generated from the sequence of control error values in the constant line current operation to an analogue direct voltage for supplying the terminal and convert the nominal direct-current value into the analogue feedback voltage in the constant line current operation.

Abstract: Embodiments related to line testing are described and depicted. A digital subscriber line testing apparatus comprises a plurality of resistors and a switching device. The switching device comprises first and second signal inputs to couple the switching device to a signal generator output, and a plurality of wire terminals. The switching device is configured to switch the plurality of resistors into a first switching state and a second switching state.

Abstract: Embodiments related to line testing are described and depicted.

Abstract: A control device for controlling a supply voltage which can be switched between a constant line current operation and a constant line voltage operation, wherein a line current, which consists of a direct current for supplying the terminal and of an alternating current for transmitting information, flows via a subscriber line of a terminal, comprising a sensing circuit for sensing an analogue input voltage dependent on the line current, a subtractor which, in the constant line current operation, subtracts an analogue feedback voltage dependent on an adjustable nominal direct-current value from the sensed input voltage for generating an analogue difference voltage, an analogue/digital converter for converting the generated analogue difference voltage into a digital difference voltage value, a digital low-pass filter for filtering a sequence of control error values out of the generated sequence of difference voltage values, a controller for generating a control value in dependence on the filtered-out sequence of