Abstract: Managing line power for network elements in an access network. In one embodiment a current sense system in a line power network is disclosed. The current sense system includes a power supply, a splitter and a sense circuit. The power supply is adapted to supply output current to a twisted pair drop. The splitter is adapted to combine communication signals and the output current on a twisted pair drop. The sense circuit is coupled to sample the output current of the power supply between the power supply and the splitter. The sense circuit is further adapted to output a sense signal that is representative of the output current.

Abstract: A reconfigurable processing unit for a digital hearing instrument includes an IS processor module, a plurality of processing units and a crosspoint switch matrix. The IS processor module receives a hearing instrument configuration. Each of the processing modules are configured to process audio signals received by the digital hearing instrument. The crosspoint switch matrix is coupled to the IS processor module and each of the processing modules, and includes at least one crosspoint switch that is configured to route audio signals between processing modules and to combine at least two audio signals. In addition, the IS processor module uses the hearing instrument configuration to program the configuration of the crosspoint switch and thereby control how the crosspoint switch matrix routes and combines audio signals.

Abstract: An ADSL/POTS filter arrangement includes a filter and a switchable return loss correction circuit coupled to one side of the filter. The switchable return loss correction circuit includes a resistor and an inductor connected in parallel, a polarity insensitive solid state switch, and a capacitor connected in series between the switch and the parallel-connected resistor and inductor. The switchable return loss correction circuit is switched on by the polarity insensitive solid state switch which is controlled by a line sensor depending on whether the POTS telephone is on or off-hook.

Abstract: A method and apparatus is provided for performing an active impedance differential current feedback. A signal is received. A current feedback of an output signal in an active feedback synthesis mode is performed based upon the signal. The active current feedback includes using an active feedback network for conditioning an output signal, converting the signal into a differential current signal, and summing at least two components of the differential current signal for performing a differential feedback.

Abstract: An isolation system with analog communication across an isolation barrier includes an isolation barrier circuit having at least one isolation element; a digital to analog circuit having an analog output connected to the isolation barrier and an input for receiving an input digital signal to be communicated across the isolation barrier; and an analog to digital circuit having an input coupled to the analog output of the isolation barrier circuit for providing a digital output signal.

Abstract: A system for use in connecting broadband voice and data signals to communications systems such as the telephone system. Due to the low pass filtering characteristics of a standard twisted pair used in conventional telephone access loops data band signals are attenuated more than voice band signals. The present invention provides apparatus and methods for interfacing data and voice band signals to a common communications medium, such as a twisted pair, while significantly reducing the influence of one frequency band on the other.

Abstract: Embodiments of the present invention relate to systems and methods for an electronic hook switch for customer premises equipment. In an embodiment, a system includes a first lead configured to be coupled to a tip wire and a second lead configured to be coupled to a ring wire. A diode bridge is coupled to the first lead and the second lead and has a positive output. A low side switch is coupled to the positive output of the diode bridge without a high side switch between the low side switch and the positive output of the diode bridge.

Abstract: A method and an apparatus provide for determining whether a data terminal equipment (DTE) device represents a compatible device lacking an independent power supply and adapted to be powered using phantom power over a wired connection from a communications device such as a switch. A detection signal may be transmitted from the communications device to an identity network connected to the DTE. A response detection signal may be returned and checked in a receiver at the communications device. A switch may then be closed to provide phantom power if the result of the check indicates that the DTE is a compatible device adapted to receive phantom power. Compatible DTE device may include telephones, Voice over IP (VoIP, IP or Ethernet) telephones, network access devices, computers, and the like.

Abstract: Detectors determine the presence of valid sinusoids for DTMF, MF-R1 and MF-R2 protocols for encoding dialed digits. The detectors split electrical signals into subbands. Energies within the subbands are analyzed to determine a presence of sinusoids corresponding to frequencies of dialed digits. In one embodiment, the detectors comprise a PS-IIR filter to split the electrical signal into the subbands. The detectors further comprise at least one bank of filters, such as notch filters, corresponding to the number of possible relevant frequencies within the respective subbands. The detectors further comprise detection logic comprising tests, which may include analyzing the output(s) from the bank of filters. Optionally, a preclassifier is employed to predetermine which filters in the banks of filters are to be executed. The detectors, typically deployed in digital signal processors, allow for an increase in the density of detectors and provide robust performance in talk-off situations.

Abstract: A detection circuit and method for detecting AC voltage pulses at a defined frequency relate to first transforming an input signal to a low-frequency signal by multiplying the input signal by a mixing frequency. This down-mixed signal can then be filtered and evaluated. The circuit is particularly suitable for identifying charge unit signals in the telephone network.

Abstract: Method and apparatus for transmitting a transmission signal via a two-core line, in particular a telephone line, in which case, with the aid of corresponding transmission devices (2, 3), two partial signals are generated and are transmitted via a respective core (A, B) of the line and the transmission signal is formed by the alternating-current difference between the two partial signals. In order to suppress common-mode components in the partial signals, a calibration is carried out in such a way that the transmission devices (2, 3) output essentially the same output level.

Abstract: A regulated power supply interface has a current feedback and voltage level shift circuit that monitors power supply output (load) current and controllably diverts current to a current reference node. A differential amplifier-based, voltage feedback and voltage level shift circuit monitors the load voltage and controllably diverts output current to the current reference node. A current mode setpoint circuit has multiple voltage dropping current paths, through one or more of which a summation of the diverted load currents are programmably directed, to generate a control voltage for controlling the operation of a pulse width modulator unit of the regulated power supply.

Abstract: A comparator-based switchmode power converter monitors the most negative of the tip and ring line voltages, to control the supply voltage to a SLIC. The voltage applied to the SLIC's power terminals is slightly higher than the sensed voltage for different loop signaling conditions, including loop start, ground start balanced ringing. The switchmode converter includes a comparator coupled to a DC-DC output node downstream of a MOSFET switch installed in a DC supply rail of a source of DC supply voltage, and coupled to a power supply terminal of the SLIC. The comparator is also coupled to a set point node, which is coupled through a voltage offset path to each of tip and ring portions of the telephone line.

Abstract: Methods and apparatus for protecting quality of service during a process involving bridge tap in a communications system are described. Bridge tap may occur during system construction, central office re-concentration, replacement projects, upgrade projects, expansion projects, and installation of back-up cables, etc. Cables, with one end connected to a point in the system, and the other end left unterminated, result in bridge tap. In the bridge tap moderator of the present invention, a plurality of termination networks are attached to a modular connector such that a separate termination load is placed across each connector terminal pair for each corresponding wire pair of the cable. Communication lines can be easily attached to the moderator thereby easily, quickly, and efficiently eliminating bridge tap on a large number of wire pairs. The bridge tap modulator apparatus and method of use also minimize the amount of time bridge tap exists during cable and/or communication device installation.

Abstract: A system for determining whether a telephone loop is capable of carrying a Digital Subscriber Line (DSL) signal. A Constant Amplitude Zero Auto Correlation (CAZAC) sequence signal is generated and transmitted through the loop plant to a central office and the received echo signal is processed using second-order statistics. The second-order statistics calculation permits determination of the echo signal amplitude and time between the echo signal and sequence signal. The echo signal amplitude and time may be used to obtain telephone loop characteristics such as loop length.

Abstract: A line interface capable of connecting to a variety of transport mediums, each having a different impedance. The line interface comprises a programmable resistor. The programmable resistor along with an external resistor provide a range of resistor values which are used to substantially match the impedance requirements of the various transport mediums.

Abstract: A method and apparatus for pre-qualifying lines with respect to estimating the insertion loss of the line is presented. End-to-end insertion loss at high frequencies is estimated from measurements made at low frequencies through the voice switch at the central office of a telephone company. An AC voltage waveform is applied to the telephone line being tested. Real and imaginary components of the resultant waveform are measured. These measurements are captured and used to estimate the insertion loss of the telephone line at frequencies in the range of 40 kHz to 300 kHz.

Abstract: An integrated line inductor and line feed resistor is disclosed. A first coil winding and a second coil winding having a select resistance are magnetically coupled to each other. The first coil winding and second coil winding are each operable to transform electric energy between a Subscriber Line Interface Circuit (SLIC) and a tip and ring (T/R) line.

Abstract: The present invention provides a method to configure the hardware and software resources in a system to utilize two physical interface boards in pairs such that their aggregate units of voice processing DSP resources can be applied to either all of a T1 board's physical interfaces or all of an E1 board's physical interfaces. This allows a single telecommunications system to run as either T1 or E1 with no additional hardware required. The present invention also provides the ability to run protocols normally associated with T1 physical interfaces on a card with only E1 physical interfaces. A method for changing the configuration from T1 to E1 and from E1 to T1 is provided as well. Additionally, the method includes configuring the system to look like a single set of contiguous T1 or E1 channels.

Abstract: A multi-services access platform is presented for supporting metallic test access in switching or multiplexing devices such as digital subscriber line access multiplexers (DSLAMs). The multi-services access platform includes a chassis within which a predetermined number of card slots are included. Each of the card slots includes a number of input/output ports. A backplane runs along the chassis and includes a metallic test access bus. The metallic test access bus is operable to selectively couple to one or more input/output ports within the line card slots of the chassis to establish one or more metallic test paths. A relay matrix may be used to provide the selective coupling for the metallic test access bus, and the flexibility provided by the configuration of the relay matrix supporting the metallic test access bus allows for a variety of different test access ports (TAPs) to be supported.

Abstract: The eavesdropping prevention system and method of the present invention provides for shunting leakage signals in a communication system. The amplifier-based coupler is constructed with amplifiers configured with a nearly-zero impedance path which effectively prevents the propagation of a leakage signal onto other communication connections which are coupled to the same communication device. Leakage signals are attenuated due to the nearly-zero impedance path, rather than propagating through the higher impedance communication connections.

Abstract: A technique for implementing impedance matching circuits 100 that use the transfer functions of each line impedance model. This technique allows implementation of an impedance match for a diverse number of line impedances reusing the same circuit 100 topology, by simply adjusting coefficients to accommodate different line impedances.

Abstract: A hybrid circuit is disclosed for effectively communicating information over a telecommunications line to which a transmitter and receiver are connected. The hybrid circuit is configured as a filter for filtering at the receiver input signals at predetermined frequencies appearing on the transmitter output and the telecommunications line. The filter circuit additionally forms a capacitive divider for scaling signals appearing at the transmitter output and canceling the scaled signals at the receiver input with related signals appearing on the telecommunications line. In one embodiment of the present invention for communicating using the ADSL protocol, the filter circuit is a first order high pass filter.

Abstract: A digital direct access arrangement (DAA) circuitry may be used to terminate the telephone connections at the user's end to provide a communication path for signals to and from the phone lines. Briefly described, a means for providing a proper hookswitch transition for a variety of international phone standards is provided. The invention may also be utilized with means for transmitting and receiving a signal across a capacitive isolation barrier. More particularly, a DAA circuitry may be utilized which satisfies many or all hookswitch transition standards without the use of additional discrete devices. The hookswitch transition standards may be satisfied by ramping down the current flowing through the hookswitch prior to transitioning the hookswitch state. In this manner the hookswitch current change as a function of time (di/dt) may be decreased. Thus, the current through the hookswitch may be actively controlled prior to switching the hookswitch from an off-hook condition to an on-hook condition.

Abstract: An application programming interface (API) enables a telephone to utilize the hardware resources of a computer that is connected to the telephone in a master/slave relationship that causes the computer to function in the manner of a peripheral to the telephone. Specifically, the telephone attached to the computer can utilize the relatively large memory capacity of the attached computer to store excess telephone-specific data and can utilize the relatively high sophistication of the processing capability of the connected computer to perform intensive data processing operations. The API allows the functionality of the telephone to be extended without requiring a telephony-equipped computer.

Abstract: A method and apparatus for enabling multiple protocol communication over a network are disclosed. A first circuit communicates first signals in a first frequency band using a first data protocol and attenuates second signals in a second frequency band using a second data protocol. The first data protocol supports a first modulation technique and a second modulation technique. A second circuit communicates the second signals in the second frequency band using the second data protocol.

Abstract: A computer to telephone interface card comprises a plurality of audio data input ports, a mixer, and a converter. The mixer receives audio input data from audio data input ports and, in real-time, generates a mixed audio output data signal at the mixer output. The converter has an output connecting to a phone line to generate and provide mixed audio output to the phone line based on the audio input data received at the plurality of audio data input ports.

Abstract: A configurable adaptive echo canceler which can perform acoustical echo cancellation (AEC) or hybrid echo cancellation (HEC) under software control. Particular parameters based on the particular application can be associated with either a suitable AEC or a suitable HEC, and the parameters are made selectable through the use of a control register. Exemplary parameters are accuracy of filter coefficients, a span select to manipulate the expected length of the echo path, a step size to adjust the adaptation of the echo cancellation, enablement of a tap update, selection of adaptation mode, center clipper selection, and sub-band or full-band echo cancellation. With the use of audio line switching, the configurable echo canceler can allow various modes of operation of the telephone, some of which may require an AEC in the installed unit and/or some of which may require an HEC.

Abstract: A hybrid system with adjustable on-chip components and a method calibrating the same invariably maximizes hybrid performance despite of on- and off-chip component mismatches and imperfections. The hybrid system has a main DAC, a replica DAC, and three or four resistors. Both DACs are directly connected to digital data. An adjustable resistor is connected to the main DAC and is calibrated such that output impedance is automatically adjusted to match an off-chip load impedance Z. A replica DAC current K is calibrated for optimum DC matching in presence of Z. An adjustable capacitor C2 is calibrated for slope-matching (bandwidth matching). If Z changes, the calibration procedure should be repeated for optimal performance. These three calibration mechanisms can be utilized individually or in combination. The present invention is compatible with both analog and digital echo-cancellers.

Abstract: A system for providing power to a local area network LAN connected device via spare wire pairs from a phantom feed LAN, the system comprising a first connector for connecting to the LAN connected device; a second connector for connecting to a LAN hub; and means for redirecting current from signaling wires of said second connector to at least one spare wire pair of said first connector.

Abstract: An adaptive interface method and apparatus for interfacing a telephony appliance such as an analog telephone, modem, fax modem, facsimile machine teleconferencing device, headset, VoIP telephone or non-compatible digital telephone to a digital, analog or hybrid telephone system, such as a private branch exchange (PBX). The interface device is suitable for use with a variety of PBX's produced by different manufacturers, despite differences in signaling characteristics between the PBX and an associated PBX-compatible telephone. The interface device is coupled between A telephony appliance and a PBX. In order to communicate the interface device “learns” the characteristics of the telephony appliance and also of the PBX. This is accomplished by: determining whether each component of the telephone system is an analog or digital device; and, if the telephone system is a digital, monitoring communications between the PBX and the PBX-compatible telephone.

Abstract: A digital input signal is analyzed by a peak detector (210) configurable to trigger a first logic signal (260) if the peak detector detects the digital input signal level crossing a certain threshold. The threshold value can be modified by an overhead. The amplifier (250) employs a plurality of supply rails of differing voltages (253, 255) as a function of the logic signals. A digital signal delay element (220) may delay the signal to allow sufficient time for the amplifier to switch between supply sources. A logic delay element (280) may delay transmittal of the first logic signal by the peak detector to compensate for signal delay caused by a filter. A hold element (270) ensures that the first logic signal is applied to the output amplifier for a given amount of time.

Abstract: Overhead voltage is allocated in a telecommunication system among different AC signals, such as POTS, on-hook transmission POTS, PPM and XDSL signals, communicated between a telephonic switch and a user device. The allocation is based on the available overhead voltage, the condition, such as impedance, of the line carrying communications to the user, and which of the signals are to be communicated.

Abstract: A central office modem (50) that includes the capability of single-ended loop testing (SELT) is disclosed. The modem (50) includes a digital signal processor (54), a codec (56), line driver and receiver circuitry (58), and a hybrid circuit (60), by way of which a subscriber loop (LOOP) can be driven and sensed. The line driver and receiver circuitry (58) may include a transformer (74a, 74b) for driving the loop (LOOP), or the output may be capacitively coupled. The line driver and receiver circuitry (58) includes active termination, by way of operational amplifiers (80a, 80b). Switches (82a, 82b; 84a, 84b) are provided to selectively enable and disable the active termination function, and to selectively bypass or include the hybrid circuit (60). This control of the line driver and receiver circuitry (58) provides the ability to calibrate out its own characteristics, providing high precision SELT measurements of the load impedance type, and of frequency domain reflectometry, and time domain reflectometry.

Abstract: A radio frequency communication system utilizing a radiating transmission line for communicating data signals is disclosed. The data signals convey digital data to remotely located data devices, including computers, equipment control systems and digital video cameras. The data signals have a wide bandwidth of about 0.5 MHz to 32 MHz. In this way, the communication system creates a local area network by means of the radiating communication line. The communication system is intended to be used in environments where radio waves do not propagate well, such as in underground environments, and in particular mines. The communication system comprises at least one amplifier connected to the radiating transmission line for periodically amplifying the data signals by demodulating the data signals to recover the data contained therein and then modulating the recovered data into a regenerated radio frequency at a power level permitting transmission and radiation of the regenerated radio frequency data signal.

Abstract: POTS splitter design which incorporates a low-pass filter which improves the voice-band return loss characteristics without sacrificing performance with regard to the voice-band insertion loss or the ADSL-band attenuation distortion. This is accomplished by replacing the inductor of the conventional POTS splitter low-pass circuit with a parallel-connected inductor and resistor.

Abstract: A communication apparatus is used to interface signals with any one of a plurality of telephony networks having different impedances. The apparatus includes memory, a processor, a digital-to-analog (D/A) converter, and an interface port. Different sets of impedance control values are stored in the memory. The processor is configured to select one of the sets of impedance control values and to serially transmit the selected set of impedance control values during a communication session. The D/A converter is configured to receive the selected set of impedance control values from the processor and to transmit analog signals based on the selected set of impedance control values. The interface port is configured to interface signals with a communication connection of a telephony network.

Abstract: An improved modem architecture and associated method that integrates modem and line-isolation circuitry so as to achieve modem functionality and system-side isolation functionality on a single integrated circuit while also providing a modem interface that allows synchronous modem transmission protocols to be implemented through an asynchronous serial interface is disclosed. For example, one such type of synchronous modem transmission protocol is the HDLC (high-level data link control) protocol. According to the techniques disclosed herein, data and control information of an HDLC protocol may be presented at transmit and receive pins of a modem/system side DAA through an UART even though the UART may be an asynchronous serial receiver transmitter. Thus, both transmit and receive data transfers of a serial modem protocol may be implemented through an asynchronous serial interface.

Abstract: A filter passing only desired frequencies is selected according to a desired level of service for copper lines. At a point of access between a loop plant and Central Office, the filter is interposed in series over a telephone service line to provide spectral containment by restricting the frequencies of transmission passing along the line. The filter is preferably mounted within a 5-pin module used in a protector block at the Central Office or remote terminal facility, interfaces with a 5-pin module, or is placed upstream or downstream of a protector block such that it does not interfere with the operation thereof. Service is activated, and the spectral containment apparatus prevents the transmission of unexpected or unintended services over the line.

Abstract: Systems and methods are described for a download booster for ADSL transmission. A method includes extending a digital subscriber loop including: coupling a telephone company central office to a customer premises via the digital subscriber loop; filtering a downstream digital subscriber loop signal at the customer premises; and amplifying the downstream digital subscriber loop signal at the customer premises. A method, includes: providing a digital subscriber loop service to a customer premises that is coupled to a telephone central office via a digital subscriber loop line; filtering a downstream digital subscriber loop signal at the customer premises; and amplifying the downstream digital subscriber loop signal at the customer premises.

Abstract: A network interface circuit that screens out transient signals and provides an indication to the line side that an actual event has occurred, so that appropriate discrimination circuitry is powered up to determine the exact nature of the actual event only when actually needed. The present invention develops an AC signal that represents the events that are desired to be detected. This AC signal is timed so that it has a sustained rate (e.g., a 1 millisecond burst) that is unlike any transient that would occur on the line. Thus, unless the incoming signal meets the timing requirements of the circuit, it is disregarded as a being a transient and no action is taken to determine the exact nature of the signal. This avoids the need to invoke the discrimination circuits that have large power requirements until they are actually needed.

Abstract: In a telecommunications transmission system using a DTM system as a multicarrier system and having at least two VDSL systems, each including a pair of modems, the at least two VDSL systems belonging to a single binder group common to both VDSL systems, a method in the DMT system for keeping DMT frames aligned to the same frame timing includes estimating the time mis-alignment and power of cross-talk DMT signals added to a received DMT signal when the estimate is used by the modem to synchronize its own frame timing to a main cross-talkers frame timing, using auto-correlation on the received signal and a delayed copy of the received signal, and detecting correlation maxima that determine the frame boundaries of different DMT components of the received signal.

Abstract: A telephone and cable television network interface device includes a first housing having first and second compartments, a terminal located in the first compartment for connection to telephone service, a terminal, located in the second compartment for connection to a telephone of a telephone service subscriber, a cover for restricting access to the first compartment and a cable television splitter. The splitter is located in the first housing and includes a second housing spanning the first and second compartments. A plurality of coaxial cable connectors, all facing the same direction, are located in the second housing. At least one connector is located in each of the compartments. The first housing includes a plurality of grooves aligned with the coaxial cable connectors. In one embodiment, the longitudinal axis of each of the coaxial cable connectors is located in the same plane. The device may also include a ground bus located in the first housing.

Abstract: 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.

Abstract: A high efficiency line driver is disclosed. The line driver may be applied with equal advantage in wired and wireless communication media to amplify data signals with a minimum of power consumption. In an embodiment of the invention a line driver is disclosed which includes: at least one amplifier, a delay element, a control signal generator and a generator. The at least one amplifier includes at least one bias supply, a signal input and a signal output. The delay element accepts as an input the data signal and delays delivery of the data signal to the at least one line amplifier for amplification. The generator is responsive to a control signal to generate varying voltage levels corresponding thereto on the at least one bias supply of the at least one amplifier. The control signal generator is responsive to the input data signal to detect peaks therein and to generate the control signal corresponding thereto in advance of delivery of the data signal to the amplifier.

Abstract: The present invention relates to broadband line drivers, comprising a cascade connection of an operational amplifier (A) and a transformer (T), which can be integrated on chip. This is obtained by putting the transformer (T) in a feedback loop between the output and the input of the operational amplifier (A).

Abstract: The invention herein is fallback function communications device comprised of a microprocessor, utilized to perform a predetermined operation and processing of a predetermined input signal and then output a corresponding signal, as well as a minimum of one relay circuit having an amplifier circuit and a relay. The terminal at the first side of the relay is connected to the telephone line tip/ring terminal, while the terminal at the second side of the relay is connected to the Public Services Telephone Network (PSTN) tip/ring terminal of the microprocessor. An off-hook detection circuit is connected to the PSTN tip/ring terminal and also connected to the ring detection terminal of the said microprocessor. A dummy load circuit is connected to the tip terminal and the ring terminal of the PSTN. As such, in the event of Voice Over Internet Protocol (VOIP) system failure, the present invention is capable of automatically switching to the PSTN and thereby maintain telephone system operation.

Abstract: A method that sends upstream a collection of data samples measured from a DSL line.

Abstract: The communications system has a transmission network for transmitting useful data and control data. Call numbers are input at a subscriber terminal. A subscriber line unit with an adjustable transmission characteristic is connected between the subscriber terminal and the transmission network. A recognition unit connected to the transmission network recognizes particular call number patterns and outputs particular control signals corresponding to call number patterns. A control unit connected between the recognition unit and the subscriber line unit sets the transmission characteristic of the subscriber line unit depending on the control signals provided by the recognition unit.

Abstract: A communication system is provided which draws virtually no loop current during a ringing burst and only draws on-hook loop current during the caller ID field. More particularly, ringer burst circuitry may be powered from the user powered circuitry by the transmission of power across the isolation barrier rather than being powered from the phone line. Thus, loop current need not be drawn from the TIP/RING lines during ringer bursts. The isolation barrier may be a capacitive isolation barrier which allows bidirectional communication and extraction of power from signals transmitted across the barrier.