A circuit for transmitting and receiving communications. The circuit includes a transmit block, a receive block, and an echo canceller, coupled to the transmit block and to the receive block, for determining an echo signal and subtracting it from the received signal, the determination of the echo signal involving a predetermined number N of coefficients calculated at the beginning of each of the communications in an initialization phase. The circuit periodically updates during communication a restricted group of coefficients chosen from among the most significant coefficients. The present invention also relates to an echo cancellation method.