SIGNALING METHOD IN IP TELEPHONE SYSTEM , IP TELEPHONE SYSTEM, AND IP TELEPHONE DEVICE

摘要

There is provided a signaling method for an IP telephony system (1) including a call terminal (10), a destination terminal having its identifier (20) and an extension terminal (30a) having its identifier and correlated to the destination terminal (20). A message having a header portion indicating the identifier of the destination terminal (20) and a payload portion indicating the identifier of the extension terminal (30a) is transmitted from the call terminal (10) to the destination terminal (20). The message transmitted is transferred from the destination terminal (20) to the extension terminal (30a). A response signal to the transferred message is returned from the extension terminal (30a) to the destination terminal (20).