SIGNALING RELAY SYSTEM AND SIGNALING RELAY METHOD

PROBLEM TO BE SOLVED: To provide a signaling relay system and method by which even terminals with different capabilities can set up a session to make communication between them without the need for the terminals to conduct signaling processing by notifying a data converter so as to relieve the load on the terminals. SOLUTION: The signaling relay system between communication terminals in a communication network where a plurality of communication terminals are interconnected, is configured to comprise a signaling relaying device and a data converter. When the signaling relaying device informs the data converter about respective capability information items of a caller terminal and a called terminal in order to cope with the case of detecting unmatched capabilities between the caller terminal and the called terminal, generates a session setup request message, where the capability information of the caller terminal is revised into the capability information of the data converter, transmits the message to the called terminal, generates a session setup response message, where the capability information of the called terminal is revised into the capability information of the data converter, and transmits the message to the caller terminal so as to set up a 2-stage session via the data converter.