Use of an echo canceller for the detection of CAS signals

摘要

A method and a communication device detect a service signal and include a converter having a first input which is connected to a communication channel for communicating with a network. An input device is connected to a second input of the converter for providing input signals to the converter. An echo canceller receives the input signals to form a replica of echo present in output signals from the converter for cancelling the echo and forming modified output signals. An output device is connected to an output of the echo canceller for receiving the modified output signals, and a service signal detector is connected to the output of the echo canceller.