| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To select one of public network 7 and an IP network 9 and connect a telephone set thereto when the telephone set can not be connected to the other communication network. <P>SOLUTION: A communication adaptor 4 for connecting the telephone set 2a to either one of the public network 7 and the IP packet network 9 is provided with a subscriber circuit 21 connected to the telephone set 2a, a trunk circuit 23 connected to the public network 7, an IP interface part 24 connected to the IP packet network 9 to convert voice information transmitted from the telephone set 2a into an IP packet and convert an IP packet transmitted from the IP packet network 9 into voice information, a switch part 22 for switching the connecting destination of the subscriber circuit 21 to either one of the trunk circuit part 23 and the IP interface part 24, and a control part for monitoring the operation of the trunk circuit 23 and the IP interface part 24, and when abnormality occurs in either one of the trunk circuit 23 and the IP interface part 24, controlling the switch part 22 to change the connecting destination of the circuit 21 to the other side. <P>COPYRIGHT: (C)2004,JPO</p> |
