Abstract: A loop carrier system includes a home local area network having plural telephone modules and a hub coupled to in-home telephone wiring. The telephone modules and the hub communicate voice signals over the in-home wiring in a dedicated frequency band above baseband POTS. The hub converts between voice signals and voice packets and is connected to a network access device for transferring the voice packets from the home local area network to a telecommunications network which routes the voice packets to a gateway. The gateway converts between the voice packets and a circuit format compatible with a local digital voice switch.

Abstract: An ADSL modem provides compensation for a nonlinear telephone impedance by predistorting transmit signals such that the voltage across the nonlinear impedance is correct independent of the impedance. Correcting the voltage across the nonlinear impedance reduces noise in the telephone due to intermodulation products generated in the voice band. The modem comprises a transmitter that includes (a) a signal source providing a source data signal and (b) a predistortion circuit for predistorting the source data signal to provide a modem transmit signal for coupling to a transmission loop having a nonlinear impedance coupled thereto. The modem device further includes a receiver for receiving a modem receive signal from the transmission loop. The source data signal comprises source digital words, each source digital word corresponding to a particular voltage level.

Abstract: In a time division multiplex digital communication system, access devices are capable of generating and detecting data sequences that are normally suppressed by end user equipment for establishing in-band communications between the access device and selected intelligent channel units (ICU's ). An ICU initiates in-band communication with the access device by transmitting a service request sequence to the access device. The access device transmits a wake-up sequence to the ICU to establish in-band communication. Once established, in-band communications can then be used to accomplish automated provisioning, performance reporting, status reporting, alarm reporting as well as other important functions.

Abstract: A system for isolating the direction of communication errors in the local loop of a digital data network is described. A Network Interface Unit (NIU) located at the customer premises typically has a loopback feature, allowing for Bit Error Rate Tests (BERT) to be performed on the local loop from a remote test system located on the data network. The NIU loopback test isolates transmission problems at the customer premises from problems on the local loop. The present invention adds test pattern generation capability to the NIU, allowing the remote test system to determine whether the transmission problem on the local loop is in the network to customer premises direction or in the customer premises to network direction.

Abstract: Loop Performance Monitoring (LPM) for DDS loops is described. Even though DDS loops have Intentional Bipolar Violations (BPVs), a Loop Coding Violations (LCVs) detection strategy based on further processing of BPVs is described. By monitoring LCVs a local loop terminating device can determine Bit Error Rate (BER).A system is described by which an Office Channel Unit (OCU) can process LCV information to determine signal quality of the signal over the incoming local loop. If the signal quality falls below a certain threshold, the OCU can cut the loop off from the DDS circuit and send control codes into the network.A system is also described where a Network Interface Unit (NIU) with the LPM system communicates incoming LCV information to the OCU using low speed signalling over the simplex path between the transmit and receive pairs. The OCU monitors incoming LCVs as well, and thus has the information necessary to determine bi-directional BER performance.

Abstract: In a time division multiplex digital communication system, access devices are capable of generating and detecting data sequences that are normally suppressed by end user equipment for establishing in-band communications between the access device and selected intelligent channel units (ICU's). In-band communication is initiated by transmitting a sequence comprising a plurality of first bytes for preventing inadvertent initiation of maintenance operations for digital devices in a particular time slot, followed by a plurality of second bytes in said time slot. In-band communications is established when the selected ICU receives a sequence comprising a plurality of said first bytes, a plurality of bytes which identify the select device and a plurality of said second bytes. Once established, in-band communications can then be used to accomplish automated provisioning, performance reporting, status reporting, alarm reporting as well as other important functions.

Abstract: Loop Performance Monitoring (LPM) for DDS loops is described. Even though DDS loops have Intentional Bipolar Violations (BPVs), a Loop Coding Violations (LCVs) detection strategy based on further processing of BPVs is described. By monitoring LCVs a local loop terminating device can determine Bit Error Rate (BER).A system is described by which an Office Channel Unit (OCU) can process LCV information to determine signal quality of the signal over the incoming local loop. If the signal quality falls below a certain threshold, the OCU can cut the loop off from the DDS circuit and send control codes into the network.A system is also described where a Network Interface Unit (NIU) with the LPM system communicates incoming LCV information to the OCU using low speed signalling over the simplex path between the transmit and receive pairs. The OCU monitors incoming LCVs as well, and thus has the information necessary to determine bi-directional BER performance.

Abstract: A quadrature coder for a two-wire digital loop communication system is described in which data is sampled and quadrature encoded by being divided into two bit streams, one of which comprises every other bit in the original bit stream and the other one comprises the remaining bits. One of the divided bit streams is delayed by 90.degree. from the other. The delayed and undelayed bit streams are then recombined and transmitted over a two-wire loop.

Abstract: Loop Performance Monitoring (LPM) for DDS loops is described. Even though DDS loops have Intentional Bipolar Violations (BPVs), a Loop Coding Violations (LCVs) detection strategy based on further processing of BPVs is described. By monitoring LCVs a local loop terminating device can determine Bit Error Rate (BER).A system is described by which an Office Channel Unit (OCU) can process LCV information to determine signal quality of the signal over the incoming local loop. If the signal quality falls below a certain threshold, the OCU can cut the loop off from the DDS circuit and send control codes into the network.A system is also described where a Network Interface Unit (NIU) with the LPM system communicates incoming LCV information to the OCU using low speed signalling over the simplex path between the transmit and receive pairs. The OCU monitors incoming LCVs as well, and thus has the information necessary to determine bi-directional BER performance.