Patent ID: 7312613

Claim:
A method for network diagnosis between a source end and a destination end coupled by a transmission line, wherein the source end comprises a transmitter, a receiver, a canceller, and a hybrid, comprising: transmitting a first test signal from the transmitter to the receiver when the hybrid is set to a first mode; extracting a plurality of first coefficients from the first test signal received by the canceller during a first period, wherein each one of the first coefficients has an index corresponding to a received order; switching the hybrid to a second mode to generate a second test signal by sending an original signal to the receiver and the destination; extracting a plurality of second coefficients from the second test signal received by the canceller during a second period, wherein each one of the second coefficients has an index corresponding to a received order; determining a first index when an absolute value of one of the first coefficients substantially exceeds a first threshold value; determining a second index and a polarity of a peak according to a referenced signal that is obtained by subtracting the first coefficients from the second coefficients; and determining a location with a cabling issue according to the first index and the second index.