A method and apparatus are disclosed for reducing crosstalk in a telecommunication
system. Broadly, the present invention utilizes a common mode signal to obtain
additional information that can be used to better approximate the transmitted signal
(by approximating and canceling crosstalk or otherwise). In accordance with one
embodiment of the invention, a modem is provided having improved crosstalk cancellation
circuitry for canceling crosstalk received on a local loop (or otherwise estimating
the remotely transmitted signal) carrying modem communications. The modem includes
a first input for receiving a signal carried on the local loop and a second input
for receiving a signal obtained from the common mode. The modem further includes
processing circuitry configured to either reduce crosstalk present in the signal
carried on the local loop, or to otherwise closely approximate the remotely transmitted
signal. Using both the first and second signals allows the processing circuitry
of the modem to obtain more accurate results.