An apparatus and method for disabling an echo canceller in a communication
channel is external to the echo canceller. The average power of the
received signal is compared to the average power of the transmitted
signal and if the received signal is more than 26 dB below the
transmitted signal, then it is determined that echo cancellation is not
required. If the received signal is less than 6 dB below the transmitted
signal, then there is double talk present and a determination can not be
made. The invention provides a low cost system for controlling echo
cancellers and can continue to monitor echo during a call. The invention
is well suited to implementation on a field programmable gate array
(FPGA) or application specific integrated circuit (ASIC).