| 摘要 |
<p>PROBLEM TO BE SOLVED: To detour a system to another communication channel and public line, when the quality of communication line is deteriorated in the communication channel of an IP network, which is being selected at present. SOLUTION: The calling side of IP trunk circuits 5 and 6 detects quality deterioration of the communication line of the communication channel in a first line connection route in the selected IP network 2. The selection suppressing timer of the calling side of the exchanges 3 and 4 counts prescribed time, when quality deterioration is considered to be restored. The calling side of controllers 23 and 24 controls the calling side of the exchanges 3 and 4 and the IP trunk circuits 5 and 6, and controls to select another communication channel of a second connection route from the communication channel of the first connection route and to detour it. It also controls the calling side of the exchanges 3 and 4 and the IP trunk circuits 5 and 6, performs control for restoring the system to the communication channel of the first connection route from the other communication channel of the second connection route, and resumes communication.</p> |
