Abstract: A method and apparatus are disclosed which provide a common handshaking protocol for the 201, 202 and 208 modems. In accordance with the invention, connection of answer modem and originate modem to the communication line is followed by a period of silence that is sufficiently long to reactivate any echo suppressors in the communication line. Thereafter at least two training sequences are transmitted, one from the originate modem to the answer modem and the other from the answer modem to the originiate modem, each training sequence being sufficiently long to train up any echo canceller in the line. The lengths of the training sequences as received are compared with their lengths as transmitted to determine if the length of the sequence was shortened by an echo suppressor. If the length of the training sequences as received are significantly shorter than their lengths as transmitted, a sacrificial carrier is transmitted at the beginning of each transmission of data in a new direction.