Abstract: A digital subscriber loop line card-installed mechanism conducts parametric measurements on the wireline to which the line card is connected, and adjusts taps of an echo cancellation operator in accordance with the response of the wireline to an electrical stimulus imparted to the wireline. The echo canceler tap coefficients are then processed to determine the location of a fault, such as a short circuit, open-circuit and the like, on the wireline. Fault information measurement data is then reported to a supervisory control location, which dispatches the appropriate technician to resolve the cause of the problem.

Abstract: An in-band communication scheme reports the results of loop performance measurements from a remote site to a test site, by deliberately injecting, into a loopback sequence of a repeated code word, a selected one of different numbers of errors. The number of errors is selectable from among a plurality of different quantification values, based upon in which of a plurality of respective ranges of loop performance parameters, measured parameter values fall. The error data is thus effectively a gray-scale type of quantification of loop performance measurement data.

Abstract: An in-band communication scheme reports the results of loop performance measurements from a remote site to a test site, by deliberately injecting, into a loopback sequence of a repeated code word, a selected one of different numbers of errors. The number of errors is selectable from among a plurality of different quantification values, based upon in which of a plurality of respective ranges of loop performance parameters, measured parameter values fall. The error data is thus effectively a gray-scale type of quantification of loop performance measurement data.