A phase of link activation during which negotiation-proceeding XID3s are exchanged between the connected link stations to establish the primary and secondary roles of the link stations, the TG number to be used, and other characteristics of the link, and during which the mode-setting command is sent and acknowledged after the primary and the secondary roles are established. Link activation may consist only of the contact phase, or it may also have either a connect phase or a prenegotiation phase or both preceding the contact phase.