A user indicates acceptance of an incoming call by sending a CONNECT message to the network. Upon sending the CONNECT message the user shall start timer T313 (specified in 9.2). If an ALERTING message had previously been sent to the network, the CONNECT message may contain only the call reference.
If a call can be accepted using the B-channel indicated in the SETUP message, and no user alerting is required, a CONNECT message may be sent without a previous ALERTING message.