A method for retiming digital telecommunications data received by a digital logger from a plurality of T-carrier type telephone lines respectively having differing clock sources ensures efficient transmission of received digital audio data to a host computer via a Universal Serial Bus (USB) interface. Also the digital logger includes volatile memory for temporarily storing digital audio data received from the plurality of T-carrier type telephone lines for: 1. ensuring that the host computer receives digital audio data correctly via the USB interface; 2. buffering the digital audio data within the digital logger during interruptions in transmission of digital audio data from the digital logger via the USB interface; and 3. reducing audible latency of speech communications.

Various examples of mechanisms, systems, methods, techniques and devices for dynamic rate adaptation in a vectored G.fast (G.9701) system are described. A first communication device may perform estimation of a residual noise to derive signal-to-noise ratio (SNR) loss for each carrier of one or more carriers with respect to a transmitting port of the first communication device. The residual noise may be an increased noise expected to be experienced by a second communication device when one or more other ports in a vectored group of a plurality of ports of the first communication device are switched off. The first communication device may adapt to the residual noise during time slots of one or more downstream symbol positions where the one or more other ports in the vectored group are switched off by dynamically changing bit-loading.

A vector DSL system includes a plurality of modems, which may be multi-port devices. Unprocessed user data is extracted from the modems and passed through a private vectoring data routing apparatus to one or more vectoring modules, such as vectoring cards. Each vectoring module includes one or more vector processors that include processing units configured to process the unprocessed user data on the basis of all modems' data for a given DSL tone grouping. Processing of the unprocessed user data removes the effects of FEXT from upstream and downstream user data and returns the processed user data to the modems using the vectoring data routing apparatus, which can be a specialized data transmission network utilizing one or more vector routers.

Upon detection of a trigger, such as the exceeding of an error threshold or the direction of a user, a diagnostic link system enters a diagnostic information transmission mode. This diagnostic information transmission mode allows for two modems to exchange diagnostic and/or test information that may not otherwise be exchangeable during normal communication. The diagnostic information transmission mode is initiated by transmitting an initiate diagnostic link mode message to a receiving modem accompanied by a cyclic redundancy check (CRC). The receiving modem determines, based on the CRC, if a robust communications channel is present. If a robust communications channel is present, the two modems can initiate exchange of the diagnostic and/or test information. Otherwise, the transmission power of the transmitting modem is increased and the initiate diagnostic link mode message re-transmitted to the receiving modem until the CRC is determined to be correct.

An Initial Profile Application Apparatus (IPAA) is operable to apply an initial profile to a modem pair connection system, the modem pair connection system comprising a first modem, a corresponding second modem and a metallic wire connection, wherein the first and second modems are operable to establish a data connection between themselves over the metallic wire connection. The IPAA comprises: a receiver; an evaluator; a line database; a comparator; a determiner; and an applicator.

Methods and apparatus are disclosed for operating an access network including data connections (19) between end-user devices (12, 14, 16, 18) and an aggregation transceiver (20) at which connections (19) are aggregated for onward connection through the network. The method comprises, for each connection, obtaining connection data for each of a plurality of monitoring periods, each comprising shorter periods, the connection data comprising performance and user activity indications for each shorter period; monitoring the performance of the connection in order to estimate a measure of its performance during a particular monitoring period that discounts performance indications obtained in respect of shorter periods within that monitoring period when the user was inactive unless activity indications in respect of corresponding shorter periods within other monitoring periods indicate that such user inactivity is anomalous; and applying a profile to the connection that is dependent on the measure of performance of the data connection.

A method implemented in a network element (NE), comprising determining, via a processor of the NE, a channel order for a set of subscriber lines at each of a plurality of subcarriers to equalize data rates of the set of subscriber lines, wherein the set of subscriber lines is coupled to a plurality of remote NEs associated with a plurality of users, determining, via the processor, parameters for a crosstalk mitigation filter for a first subcarrier from the plurality of subcarriers according to channel responses of the set of subscriber lines at the first subcarrier and a first channel order from the channel orders for the first subcarrier, and sending, via a transmitter of the NE, parameters of the crosstalk mitigation filter to facilitate joint processing of data of the plurality of users for crosstalk mitigation.

An apparatus comprising a receiver coupled to a digital subscriber line (DSL) between an exchange site and a customer premise equipment (CPE) and configured to send a feedback error message to train a precoder coupled to the exchange site, wherein the feedback error message comprises a plurality of error components and an indication of a quantity of bits per error component, a quantization accuracy per error component, or both. Included is a method comprising sending an error feedback message to a DSL crosstalk precoder to train the crosstalk precoder, wherein the error feedback message comprises an error vector and a quantization scaling factor of the error vector.

Automatic testing/analysis of local loops of telecommunications networks includes obtaining bits-per-tone data for a local loop of a telecommunications network and generating a bit value string from the bits-per-tone data. The bit value string is then analyzed to determine whether it includes a bit pattern indicative of an impairment of the local loop. Further approaches for automatically testing local loops of telecommunications networks include obtaining attenuation data for multiple tones carried by the local loop and determining whether the attenuation data falls below thresholds for providing a service using the local loop.

A method of determining when there has been a change in the modem power state of a modem connected to a digital subscriber line. An Uncalibrated Echo Response (UER) trace is obtained from the digital subscriber line by running a Single Ended Line Test (SELT) on the line. This UER trace is compared to a historical (baseline) UER trace from the same line. A difference in the two traces in a higher frequency range (for example, DS3 for a VDSL line), is indicative of a possible modem power state change.