Patent ID: 7212521

Claim:
A method, comprising the steps of: dialing a telephone number from a source IP terminal in an IP-PBX system; transporting said dialed telephone number from said source IP terminal; seizing a relevant destination station group in response to said dialing when a dialing digit corresponding to a general directory number of a station group is transported from said source IP terminal; receiving an acknowledgement signal for said seizure by said source IP terminal from said destination station group; determining whether said dialed telephone number corresponds to a destination legacy terminal or a destination IP terminal in said destination station group; seizing a gateway channel of said dialed telephone number when said dialed telephone number corresponds to a legacy terminal; providing a ring back tone to the source IP terminal and ringing the destination IP terminal when said dialed telephone number corresponds to an IP terminal; and ringing the destination legacy terminal and sending a ring back tone to said source IP terminal when destination terminal is a legacy terminal.