CALLBACK SYSTEM AND METHOD IN IP PHONE, AND PROGRAM AND RECORDING MEDIUM

PROBLEM TO BE SOLVED: To provide a callback system in an IP phone system capable of carrying out callback processing by an instruction from a relay server at interruption from a caller terminal and ensuring a line resource of an IP phone terminal by the relay server side so as to thereby prevent a speech of emergency notice from being interrupted. SOLUTION: The callback system includes: the IP phone relay server for establishing a first connection session between respective IP addresses of a caller side and a receiver side; a connection session hold means for holding the first connection session on the basis of the reception of an interruption request signal from the caller side; a call transmission instruction means for instructing the caller to perform origination to the receiver side on the basis of the holding by the connection session hold means; a session switching means for establishing newly a second connection session between the caller side and the receiver side on the basis of the call transmission based on the call transmission instruction and interrupting the first connection session; and a session interruption means for interrupting the second connection session on the basis of an interruption request signal from the receiver side. COPYRIGHT: (C)2006,JPO&NCIPI