RING BACK TONE PROVISION DEVICE AND RING BACK TONE PROVISION METHOD

PROBLEM TO BE SOLVED: To prevent generation of a situation in which a ring back tone RBT does not arrive at a user of a call origination terminal or a plurality of ring back tones are overlapped in a communication path being established, in the case that VoIP networks of a plurality of business companies are directly interconnected without using Public Switched Telephone Networks (PSTN).SOLUTION: On a gateway device 30 for performing interconnection between a plurality of business companies is mounted a function of a ring back tone provision device. The ring back tone provision device, which comprises a RBT sound source 31, determines the necessity of sending a ring back tone before establishing, by a call of a call origination terminal 11, a communication path between the call origination terminal 11 and a call incoming terminal 21; and, when sending a ring back tone is necessary, sends a ring back tone generated inside toward the call origination terminal 11. The necessity of sending a ring back tone is determined depending on whether or not a media packet comes from a call incoming side network 20. The determination is performed by monitoring actual media for a given time or on the basis of a content of a SIP header, SDP information, or the like.SELECTED DRAWING: Figure 1 【課題】公衆交換網（ＰＳＴＮ）を使わずに複数事業者のＶｏＩＰ網を直接相互接続した場合に、通信路の確立の際に発端末のユーザに呼出音ＲＢＴが届かない状況が生じたり、複数の呼出音が重複するのを防止すること。【解決手段】複数事業者網の間を相互接続するゲートウェイ装置３０に、呼出音提供装置の機能を搭載する。この呼出音提供装置は、ＲＢＴ音源３１を備え、発端末１１の呼により発端末１１と着端末２１との間の通信路を確立する前に、呼出音送出の要否を判定し、呼出音送出が必要な場合には内部で生成した呼出音を、発端末１１に向けて送出する。呼出音送出の要否は、着側網２０からメディアパケットが流れてくるか否かにより判定する。実際のメディアを一定時間監視するか、またはＳＩＰヘッダ、ＳＤＰ情報等の内容に基づき判定する。【選択図】図１