The process in an xDSL transceiver transfers into a fast retraining sequence when the cause of an error on a telephone circuit is a change from an off hook state to an on hook state of a telephone instrument, a signal indicating an inversion of polarity of a signal on the telephone circuit, a change from an on hook to an off hook and when a handshake waiting time has passed without detecting a predetermined signal on the telephone circuit, or when the predetermined signal is detected within the handshake waiting time. The handshake waiting time can be updated in accordance with a dial pulse width, the maximum number of digits in the dial pulse signal, and the maximum number of pulses in one digit, or depending on whether or not the dial pulse comes from NTT.