An Internet Protocol telephony exchange system and a call control method
thereof. The exchange system integrates an IP terminal and a legacy
terminal in a single exchange system, controls a call of the IP terminal
in the same manner as an extension subscriber, and contains at least one
IP terminal connected to the IP network. The IP terminal contains a user
interface for generating user information or converting received user
interface information into information of a user-identifiable state, and
performs a VoIP function in compliance with one or more of a H.323, a
MGCP and an SIP protocol procedure. The IP network is connected to an IP
driver and an IP-PBX (Internet Protocol-Private Branch Exchange). The IP
driver controls an IP end point at which the IP terminals are positioned,
upon receiving IP terminal connection information and call control
information based on H.323/MGCP/SIP protocol procedure.