TELEPHONE NUMBER INVESTIGATION DEVICE, TELEPHONE NUMBER INVESTIGATION METHOD, TELEPHONE NUMBER INVESTIGATION PROGRAM, AND TELEPHONE NUMBER INVESTIGATION INFORMATION PROVISION SYSTEM

摘要

Research concerning the usage status of telephone numbers in IMS networks, NGN networks, and IP telephone networks is achieved using the non-ringing of an incoming call by using an IMS interconnection interface or the like for an inter-business interconnection and transmitting a specific message in SIP for rejecting an incoming call. Additionally, the telephone number usage status of a telephone is determined regardless of the type of incoming call network.　A telephone number investigation device 10 is connected via an NGN network to a telephone connected to at least an IMS network or a VoIP network, which are incoming call networks, and comprises a message exchange control unit 12 that imparts a first SDP parameter to an INVITE request for a telephone subject to investigation, transmits the INVITE request to an incoming call network selected by an NGN network 20, and receives a first response message from the incoming call network. If the first response message is "200 OK" or the first SDP parameter is exchanged, the message exchange control unit 12 determines that the incoming call network is the VoIP network. If the first SDP parameter of the first response message is not exchanged and the first response message is a first error code, the message exchange control unit 12 determines that the incoming call network is the IMS network.