Abstract: Systems and methods for controlling transmission of signals are described. A camera-side modem is configured to receive two signals from a video camera and to extract a received passband signal from a transmission line. A detector in the camera-side modem generates an enable signal when the received passband signal is identified. The enable signal is used to control transmission of at least one of the baseband video signal and the passband video signal. The passband signal may be identified by an estimate of mean square error in a quadrature amplitude demodulator, a measurement of reliability provided by a constellation detector, a measurement of reliability based on a sequence of frame synchronizations and/or an estimate of mean square error in an equalizer. The detector may monitor a gain factor in an automatic gain control module of the camera-side modem and/or a magnitude of the received passband signal.

Abstract: Through the use of a least squares minimization concept, the loop length, the number of bridged taps and length of the bridged taps on a transmission line can be determined from readily available modem data. In particular, the loop length, the number of bridge taps and the length of bridged taps can be estimated by comparing a measured frequency domain channel impulse response of the transmission line to a model of a loop that is comprised of multiple sections and multiple bridge taps.

Abstract: A radio equipment controller includes a calculator that calculates a delay amount by subtracting from a given maximum delay amount an internal delay amount of a radio equipment and a delay amount of a cable, the radio equipment modulating and transmitting orthogonal frequency division multiplexing (OFDM) symbols, and the cable connecting the radio equipment and the radio equipment controller that creates the OFDM symbols, a detector that detects a beginning of the OFDM symbols from data that is inputted into a buffer that stores data of the OFDM symbols, and a delay controller that determines a transmission timing of the OFDM symbols so that the transmission timing of the beginning of the OFDM symbols becomes a timing that is delayed by the calculated delay amount after a reference signal with a specific period.

Abstract: A diagnostic engine for remotely determining global line characteristics of a xDSL telecommunication line from an access node location. The diagnostic engine comprises first, second, and preferably third, measurement means adapted to measure respectively first, second and third line characteristics according to three distinct measurement techniques such as MELT, SELT and DELT. The diagnostic engine further comprises combining means able to combine the measured line characteristics in order to derive thereof global line characteristics or information relative to the physical state of the line as well as possible consequences on DSL service. By combining the three measurements in the combining means, the resulting global line characteristics of the line are improved with respect to performing separately interpretations of the three measurements.

Abstract: Methods and apparatus are provided for pseudo asynchronous testing of receive paths in serializer/deserializer (SerDes) devices. A SerDes device is tested by applying a source of serial data to a receive path of the SerDes device during a test mode. The receive path substantially aligns to incoming data using a bit clock. A phase is adjusted during the test mode of the bit clock relative to the source of serial data to evaluate the SerDes device. The source of serial data may be, for example, a reference clock used by a phase locked loop to generate the bit clock. The phase of the bit clock can be directly controlled during the test mode, for example, by a test phase control signal, such as a plurality of interpolation codes that are applied to an interpolator that alters a phase of the bit clock.

Abstract: A system and method for performing a first diagnostic test on a first class of service on a network link during a current measurement period, performing at least one further diagnostic test on a second class of service on the network link during the current measurement period, determining whether an alert was present during a previous measurement period and generating a current failure alert based on results of the first and the at least one further diagnostic tests if an alert was present during the previous measurement period.

Abstract: The invention relates to a method, an arrangement and a device for transmitting information between a central unit (DSLAM) and at least one decentralised unit (TN1, TN2, TN3) in a communication network. During, for example, the training phase in a decentralised unit (TN1, TN2, TN3), a distance between the at least one decentralised unit (TN1, TN2, TN3) and the central transmission unit (DSLAM) is estimated and a value (kl0) representing said distance is transmitted to the central unit (DSLAM). In the central unit (DSLAM), a value (kl0?) representing a fictional distance is calculated using the transmitted value (kl0) and said value (kl0?) is transmitted to the decentralised unit (TN1, TN2, TN3). Subsequently, information is transmitted in accordance with the value (kl0?) representing the fictional distance.

Abstract: A user equipment is provided. The user equipment comprises a processor that, when the UE goes out of service area of a first cell, is configured to search for a suitable cell before the UE loses a connection to a network by checking for a suitable cell among cells proximate to the first cell, based on a timer before the UE loses the connection to the network.

Abstract: Methods and apparatus for maintaining the maximum achievable data rate on a DSL line, up to and including a rate to which a user subscribes is described. Performance monitoring is conducted on the DSL line on an ongoing basis to determine noise margins in each direction. Each noise margin is compared against pre-determined decreasing/increasing thresholds to determine whether the line characteristics dictate a data rate change without loss of synchronization. The invention supports dynamic provisioning changes including application driven service level change requests, e.g., new bandwidth-on demand services. In some embodiments, a combination of existing and new embedded operations channel (EOC) messages are used to implement the modem data rate changes. New EOC messages may be implemented using some of the reserved and/or vendor proprietary Opcodes currently permitted. Modem assigned data rate changes are implemented without a disruption of service, e.g.

Abstract: A system for correlating a subscriber unit to a physical port in a point to multipoint wire line network is disclosed. An installer is prompted to manually input a location code associated with the subscriber. The location code in the subscriber unit is received, and is transmitted via the network to a central repository. The location code is stored in the central repository toward associating the location code with the physical port.

Abstract: Diagnostic testing of a telephony line card device and corresponding line card is initiated using an initiation MIB. Responding to an instruction from a main processor that a query has determined that an initiation MID is Set, line card processor circuitry begins a predetermined series of diagnostic testing. Results for the diagnostic testing are stored in a register coupled to the line card processor circuitry. After testing completes, the main processor, which is coupled to the line card processor, retrieves the results information from the line card register, converts the information to one or more results MIB(s) and stores the results MIB(s) as an instance(s) to a memory coupled to the main processor. The result MIB instance(s) is/are made available to a local or remote device via port coupled to the line card device. A permissive MIB may be queried to determine whether diagnostic testing is permitted.

Abstract: Through the use of a least squares minimization concept, the loop length, the number of bridged taps and length of the bridged taps on a transmission line can be determined from readily available modem data. In particular, the loop length, the number of bridge taps and the length of bridged taps can be estimated by comparing a measured frequency domain channel impulse response of the transmission line to a model of a loop that is comprised of multiple sections and multiple bridge taps.

Abstract: Methods, systems, and computer readable media for remotely evaluating and controlling VoIP subscriber terminal equipment using test calls, status queries, and usage statistics are disclosed. In one embodiment, a method includes initiating test calls with VoIP subscriber terminal equipment and obtaining test call results. The method further includes analyzing usage information regarding the VoIP subscriber terminal equipment and determining subscriber terminal device usage results. The method also includes remotely querying the VoIP subscriber terminal device and determining subscriber terminal equipment state information.

Abstract: A phone test set provides modem capability in a hand held device, enabling bi-directional data communications. Demodulation is provided by sampling digitized incoming phone line signals at 4 times carrier frequency, and employing values representing 0 and 90 degree samples to extract the information signal.

Abstract: While determining a leak resistance of a subscriber connection line provided, for example, with two wires in a communication network, a capacitor connected between two said wires is discharged prior to measuring leakage currents. For this purpose, prior to be connected to a high resistance of the other wire, the measurable wire and the other mentioned wire are supplied with a constantly falling and increasing voltage. For that, the final value of said tensions is determined in such a way that, when the connection to the high resistance of the other wire is produced, the voltage of said wire is equal to 0 volt. The leakage current is measured only when the discharge process is over, thereby making it possible to avoid an incorrect measurement caused by a current coming from the capacitor.

Abstract: An electric circuit for amplifying an xDSL signal comprises an operational amplifier and a signal monitoring circuit. The operational amplifier is configured to amplify the xDSL signal, is powered by a variable voltage supply and has a gain which is adjustable by an operating mode control signal. The signal monitoring circuit is activated by the operating mode control signal and is configured, when activated by the operating mode control signal, to generate a control signal to adjust the voltage of the variable voltage supply in order to adjust the maximal signal swing of the output signal of said operational amplifier. The control signal is generated by comparing the amplitude of the xDSL signal applied to the electric circuit with an amplitude threshold value.

Abstract: A method and system for managing a line topology is provided by the embodiments of the disclosure. The method for managing a line topology includes obtaining an actual transfer function of the line according to the actual transfer function of the line and a transfer function of the bridge tap model, estimating a diameter and length of the bridge tap of the line and a diameter and length of the trunk line of the line according to the estimated diameter and length of the bridge tap and the diameter and length of the trunk line, obtaining a transfer function of the line model that includes the location parameter of the bridge tap by comparing the error between the actual transfer function and the transfer function of the line model which includes the location parameter of the bridge tap, estimating the position of the bridge tap according to the estimated diameter and length of the trunk line and the diameter and length of the bridge tap and the location of the bridge tap, and generating a topology of the line.

Abstract: A system includes at least one adaptive filter coupled to a first communication channel and at least one other communications channel. The at least one adaptive filter includes at least one set of adaptive filter coefficients. A memory stores at least one predetermined set of filter coefficient thresholds. The filter coefficient thresholds may be indicative of channel faults, channel to channel faults or a length of the channel. A controller is configured to compare the set of filter coefficients to the predetermined set of filter coefficient thresholds. The controller is configured to determine the information about the channels based on compare results.

Abstract: A system for testing a conductor of a structure can include a test device connected to the conductor. The test device is configured to test an electrical characteristic of the conductor and to produce a test result based at least in part on the electrical characteristic. A service provider network may be configured to communicate with the test device to initiate a test and/or to obtain the test result. A customer may use a computing device to obtain information regarding the test result, as well as guidance for troubleshooting and resolving a problem detected with the electrical conductor, such as a fault.

Abstract: A system for testing a conductor of a structure can include a test device connected to the conductor. The test device is configured to test an electrical characteristic of the conductor and to produce a test result based at least in part on the electrical characteristic. A service provider network may be configured to communicate with the test device to initiate a test and/or to obtain the test result. A customer may use a computing device to obtain information regarding the test result, as well as guidance for troubleshooting and resolving a problem detected with the electrical conductor, such as a fault.

Abstract: A switched multi-lead test adapter is described. The multi-lead adapter has a main lead and a plurality of test leads. Each lead is connected to a switch that selects one of the test leads for connection to the main lead, or for connection to another test lead. The switch allows only one conductive path between the leads, so that the remaining, unselected leads to not cause interference on an active telecommunication wire, such as a DSL line. The test leads include multiple terminating connectors for connecting to various terminal blocks and cabling systems.

Abstract: Systems and methods for performing loop analysis are described. Some embodiments are directed to determining loop characteristics such as loop gauge, loop termination, and straight-loop departure. One embodiment includes a method for performing loop length estimation which comprises receiving an un-calibrated echo signal for a loop under test using frequency domain reflectometry single-ended line testing (FDR-SELT), a region associated with the loop under test, and a platform type. The method comprises classifying the loop under test and outputting a loop length estimate based on the classification of the loop under test and based on one of a ripple-period approach and a template-matching approach.

Abstract: Disclosed is a method and system for evaluating and troubleshooting a DSL system in a plurality of DSL systems having a common static characteristic. The plurality of DSL systems are ranked based on a ranking characteristic different than the common static characteristic.

Abstract: Methods and apparatus are provided for pseudo asynchronous testing of receive paths in serializer/deserializer (SerDes) devices. A SerDes device is tested by applying a source of serial data to a receive path of the SerDes device during a test mode. The receive path substantially aligns to incoming data using a bit clock. A phase is adjusted during the test mode of the bit clock relative to the source of serial data to evaluate the SerDes device. The source of serial data may be, for example, a reference clock used by a phase locked loop to generate the bit clock. The phase of the bit clock can be directly controlled during the test mode, for example, by a test phase control signal, such as a plurality of interpolation codes that are applied to an interpolator that alters a phase of the bit clock.

Abstract: 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.

Abstract: A method and arrangement for estimating line insertion loss of a customer transmission line at a frequency (f1) or a plurality of frequencies. Values of line insertion loss for at least two reference transmission lines are pre-measured at each frequency and stored in a memory. A calibration quantity representing an amplitude of a far-end Time Domain Reflectometer (TDR) reflection is also measured for each of the reference transmission lines. The pre-measured line insertion loss of each reference transmission line is then calibrated by the calibration quantities of the reference transmission lines. The calibration quantity for the customer transmission line is then measured, and an estimate of the line insertion loss at each frequency for the customer transmission line is generated based on the calibrated line insertion losses of the reference transmission lines and the measured calibration quantity of the customer transmission line.

Abstract: A communication system comprises a plurality of line cards having transceivers coupled to a plurality of subscriber lines. Each line card has at least one active transceiver within the same vectoring group, and each line card also has vector logic capable of cancelling crosstalk induced by an active transceiver that is a member of the vectoring group. In the event of a vectoring fault that prevents a line card from receiving vectoring information from at least on other line card, the vector logic is configured to disable vectoring for the interferers affected by the error in order to prevent vectoring operations based on obsolete vectoring coefficients from adversely affecting the quality of the communicated signals. The transceivers communicating signals affected by the suspended vectoring operations are also configured to adjust their constellation density profiles, thereby reducing their data rates, to accommodate the increased noise level resulting from the loss of vectoring.

Abstract: A system and method for generating one-way speech signal samples may include, in a telecommunications network, establishing a call connection between a far-end telephone and a near-end telephone. A resistance component may be selectively configured in parallel with the far-end telephone, where the resistance component has a value representative of resistance produced by the far-end telephone being off hook. A speech signal being communicated from the near-end telephone may be recorded.

Abstract: A system and method for assisting telephone service technicians in repairing communications lines may include storing test parameters for testing operation of a communications line. An operational parameter of communications over the communications line may be tested and a determination as to whether the operational parameter meets an operational criteria established by at least one of the test parameters may be made. The measured operational parameters and a test result indicator may be stored. If the operational parameter met the operational criteria, then an indication that the operational parameter passed a test may be made. Otherwise, (i) an indication that the operational parameter did not pass the test, (ii) possible causes for the operational parameter failing the test, and (iii) recommendations for correcting at least one possible problem that lead to the operational parameter not passing the test may be displayed for a technician.

Abstract: An apparatus for estimating far-end crosstalk RDS-FEXT, i (fd) or an end (C1-2) of a communication line (C1) furthest from a transceiver (10-1) to which the communication line (C1) is connected. The apparatus is configured to: measure upstream noise RUS-Noise(fu) at an upstream frequency (fu), the up stream noise RUS-Noise(fu) induced in the communication line (C1) due to the crosstalk; select a downstream frequency (fd) for which the far-end crosstalk RDS-FEXT, i (fd) is to determined; and estimate the far-end crosstalk RDS-FEXT, i (fd)? as a function of the upstream Noise RUS-Noise(fu), the upstream frequency (fu) and the downstream frequency (fd). An apparatus reversing upstream and downstream features, a system, a computer readable medium and related methods are also described.

Abstract: A method and loop qualification unit for determining loop parameters of a topology of a twisted pair loop for a digital subscriber line system. The parameters are represented by a vector that receives a measurement of a SELT parameter measured at one end of the loop and a measurement of a DELT loop transfer function measured at both ends of the loop. A first model generator generates a first model for the SELT parameter and a second model generator generates a second model for the DELT function based on the loop parameters represented by the vector. A processor then determines the parameters by minimizing the differences between the first model and the SELT parameter, and the second model and the DELT function. The determined parameters are represented by the vector that provides the minimization.

Abstract: The invention discloses an access apparatus and method for digital subscriber line test. The apparatus includes: one or more distributed access matrix control modules, one or more distributed access matrixes; and a power converter module. The distributed access matrix control module is connected to a test module and at least one of the one or more distributed access matrixes which is under the control of the distributed access matrix control module, and is configured to send a test task initiated by the test module to the at least one distributed access matrix and report a message from the at least one distributed access matrix to the test module. The distributed access matrix is configured to connect a tested subscriber in accordance with the test task and report an access success message to the distributed access matrix control module.

Abstract: A set of techniques includes devices, methods, and user interfaces, capable of conducting proactive automated tests of a wireless system, and capable of operating while the wireless system is conducting its normal operations. A diagnostic device not controlled by the wireless system controls drivers and clients in that wireless system's access points, with the effect that the diagnostic device can inject message traffic into the wireless system while simulating clients of that system. The wireless system responds to that traffic and those simulated clients as if real clients were generating substantially real traffic for the system to handle. The diagnostic device can initiate messages from within that wireless system, can force those messages to traverse selected trajectories in that system, and can measure aspects of that system in response to those messages. Trajectories might include specific wireless devices, specific wireless parameters, and specific physical paths.

Abstract: Embodiments for connecting and disconnecting a first pair of conductors of a jack from a second pair of conductors of the jack, the first pair of conductors configured to connect to a first line and the second pair of conductors configured to connect to a secondary line, detecting a voltage or a current on the secondary line while the second pair of conductors is disconnected from the first pair of conductors, and notifying a user in response to detecting the voltage or the current on the secondary line while the second pair of conductors is disconnected from the first pair of conductors are disclosed.

Abstract: Apparatus, methods and articles of manufacture to predict vectored digital subscriber line (DSL) performance gains are disclosed. A disclosed example method includes determining a model coefficient of a noise-to-margin ratio (NMR) model from performance data measured for a DSL subscriber loop prior to provisioning of vectoring for the DSL subscriber loop, computing, using the model coefficient, a first NMR value with disturbers enabled and a second NMR value with disturbers disabled, and estimating an expected vectoring performance gain for the DSL subscriber loop based on the first and second NMR values.

Abstract: Example methods, apparatus, and articles of manufacture to trigger preemptive maintenance of vectored digital subscriber line (DSL) systems are disclosed. An example method includes obtaining a value representing crosstalk coupling between a first subscriber loop and a second subscriber loop, the first and second subscriber loops belonging to a vectored DSL group of subscriber loops, determining whether to automatically perform a diagnostic test on the first subscriber loop based on the value, submitting a trouble ticket for the first subscriber loop based on a result of the diagnostic tests, and generating a maintenance report for the vectored DSL group based on the value and the results.

Abstract: Methods for detecting and recovering from client-link, server-link, and server-node failures are disclosed. One method comprises providing a dual link architecture. A Link-Status-Notice (LSN) message detailing at least one phone client associated with the client-link failure is sent from a primary telephony server to a secondary telephony server via a server-link. A type of redirect command is sent from the secondary telephony server to the at least one phone client associated with the client-link failure via a secondary client-link. The type of redirect command is based on a content of the LSN message.

Abstract: Method, corresponding apparatus and system are provided for transparently testing replacement functionality and optionally migrating subscribers on analog phone lines, served, for example, by PSTN Class 5 elements, to Next Generation Network (NGN) elements when copper co-termination is leveraged. According to an exemplary method, a telephone line for a telephone number is accessed through a metallic test access circuit of an analog network element and it is determined if the telephone line is available to test. If the telephone line is available to test, a port of a Next Generation Network element corresponding to the telephone number is activated, and it is determined whether a copper connection to the port of the Next Generation Network element is operating properly based on a voltage level received through the analog network element.

Abstract: A problem detection and repair system receives a trouble indication indicating a problem with a network. The trouble indication may be the result of automated monitoring of the network, or a user of communication services contacting an operator of the network to report trouble. Communication services may include telephone service, television service, Internet service, and other services delivered via a network. The trouble indication may be paired with the user's account, and one or more status determinations may be made prior to handing the user to a support person. Based on the results of the status determinations, problems may be detected, and repairs automatically attempted. If needed, the user may be forwarded to a support person along with the results of the status determinations and any attempted repairs.

Abstract: An automated system and associated methods that can be used to meet government compliance regulations are provided for testing and tracking the administration of Calling Line Identification (CLID) and Calling Party Name Identification (CPNID) information on various telephone lines (traditional circuit-based voice and evolving packet-based voice and data) for telecommunications systems. These systems can include large or small private branch exchange (PBX), key systems and equivalents, or Voice over Internet Protocol (VoIP) Call Management Servers. Capturing and recording CLID and CPNID on dial tone tests for any site location have been automated. Capabilities for recording, alerting, and reporting necessary data for internal and external auditing are provided. Centralizing real-time and historical records on phone line installation and modification activities can be generated and maintained. Verification of valid answer results for consumers' returned calls inbound to site locations can be performed.

Abstract: A phone test set provides modem capability in a hand held device, enabling bi-directional data communications. Demodulation is provided by sampling digitized incoming phone line signals at 4 times carrier frequency, and employing values representing 0 and 90 degree samples to extract the information signal.

Abstract: Through the use of a least squares minimization concept, the loop length, the number of bridged taps and length of the bridged taps on a transmission line can be determined from readily available modem data. In particular, the loop length, the number of bridge taps and the length of bridged taps can be estimated by comparing a measured frequency domain channel impulse response of the transmission line to a model of a loop that is comprised of multiple sections and multiple bridge taps.

Abstract: A loop polarity auto-reversing system 100 of a U interface is disposed in a line terminal 10 connected to a digital service unit 20 via the U interface. The loop polarity auto-reversing system includes a current detection module 101, a loop polarity determining module 103, and a loop polarity reversing module 105. The current detection module is for detecting whether there is loop current at the U interface. The loop polarity determining module is for determining whether a loop polarity of the U interface is correct if there is loop current. The loop polarity reversing module is for reversing the loop polarity of the U interface if the loop polarity is incorrect. An auto-reversing method for reversing the loop polarity of the U interface is also provided.

Abstract: A technique is disclosed for selectively providing access to a network node for testing and verification associated with a testing classification and requests are received from a network component to initiate a call via the net-work node. If it is determined that with the testing classification, service is provided via the network node.

Abstract: Systems and methods for checking broadband network components are provided in which an automated interactive system permits a field technician to check various conditions of a communication line or other broadband network components without the assistance of a support technician. While options to request assistance from a support technician are provided, the automated interactive system permits the field technician to perform various functions on a communication line without additional assistance, especially for routine tasks. The automated interactive system, therefore, removes efficiencies that may be associated with conventional approaches for checking broadband network components.

Abstract: The present invention provides a system and method for a computer controlled test system in which the computer can change and monitor the compound observable state of an electronic device or telephone during testing procedure. In the preferred embodiment of the invention, the compound observable state of the electronic device includes a display bit map file or the status of lights or buttons. The compound observable state can be evaluated by the computer in real-time to alert nearby operators of a failure (i.e. a telephone that needs to be rebooted) or malfunction (not rising to the level of a failure). Also, the data related to the compound observable state can be stored in the computer for later review to assist in debugging the telephone's software.

Abstract: The present invention relates to a wired transmission line testing method for determining at least one physical characteristic of a wired transmission line where the wired transmission line is coupled between a first line transceiver device and a second transceiver device. The wired transmission line testing method first comprises the steps of a first transceiver sending a first known excitation signal over the wired transmission line and subsequently the step of the first transceiver and the second transceiver both generating a first representation of a received signal respectively including reflected or forwarded portions of the known excitation signal and third a processing part deriving at least one physical characteristic of the wired transmission line based on the first representations generated by the first transceiver and the second transceiver.

Abstract: A method and apparatus for mechanizing the currently manual ADSL loop testing process is disclosed. In one embodiment, an automated loop testing device is disclosed, where the loop testing device has a pair of terminals, e.g., RJ-11 jacks on both sides of the device. The jack on one side connects to inside wiring which, in turn, connects to an ADSL modem. The other jack connects to an outside line which, in turn, connects to a central office of a network provider. In operation, the present device detects a line voltage reversal and then disconnects the input line to the ADSL Modem. When the voltage returns to normal, then the device behaves normally by being closed, essentially acting as a pass through device and again connects the input lines to the output lines.

Abstract: Worldwide In-country live telephone number testing is performed by a human tester located in a specific country using local Public Switched Telephone Network (PSTN) access to make outbound test calls in order to test telecommunications Quality of Service (QoS). International telephone communication has become increasingly vital in the areas of customer service, sales, and the global business cycle which have come to increasingly depend on international telephone communication. The QoS criteria tests functions including, but is not limited to: correct message; message in proper language; Dual Tone Multi Frequency (DTMF) prompts working; static; echo; cross-talk; fading in & out of conversations; speech volume; pass codes; leader pins; and the like. The results of QoS tests allow early detection of problems before those problems become serious business issues.

Abstract: A method of evaluating the characteristics of a subscriber loop associated with a customer modem comprises the steps of receiving line probing data from the modem and analyzing the line probing data to determine the circuit characteristics of the subscriber loop which relate to communication rate performance. The method generates a gain slope value as a function of the line probing data which is indicative of the length of the subscriber loop. The method also generates a loaded slope value as a function of the line probing data which is indicative of an inductive load on the subscriber loop. The method also generates an A/D value as a function of the line probing data which is indicative of an analog-to-digital and digital-to-analog conversion on the subscriber loop. The method then outputs an expected communication rate for the subscriber loop as a function of the gain slope, loaded slope, and A/D values, thereby providing a circuit analysis of the customer subscriber loop.