Patent ID: 8767521

Claim:
A system for performing a single ended line test (SELT) of a selected subscriber line within a bundle of in-service subscriber lines each supporting frequency division multiplexed multi-tone modulated XDSL communications, thereon; and the system comprising: a crosstalk cancellation module coupled to the subscriber lines and configured to cancel crosstalk between the selected subscriber line under test and the in-service subscriber lines; a single ended line testing (SELT) module coupled to the crosstalk cancellation module and configured to perform SELT testing with the crosstalk cancellation module to cancel crosstalk between the selected subscriber line and the in-service subscriber lines during testing; thereby isolating the selected subscriber line under test from the in-service subscriber lines; a probe generator to generate a probe signal on the selected subscriber line; and a controller coupled to the crosstalk cancellation module and the probe generator to control timing alignment of the probe signal with existing frame boundaries on the in-service subscriber lines and to communicate information corresponding to the probe signal to the crosstalk canceller module, thereby enabling the crosstalk cancellation module to cancel at least Far End Crosstalk (FEXT) disturbance from the probe signal on the selected subscriber line under test into the victim in-service subscriber lines.