| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a phone system that can avoid a temporary speech fault in the case of utilizing the Internet. SOLUTION: A caller side 1st phone 2031 and a called party 2nd phone 2032 are connected not only to the Internet 201 through switches 2041, 2042 and tracking gateways 2051, 2052 but also to a PSTN 202. Each of the tracking gateways 2051, 2052 is provided with a packet reception monitor section that monitors packets received through the Internet 201 and switches a speech path from the Internet 201 to the PSTN 202 when a speech quality level exceeds a prescribed threshold value and deteriorates. Thus, the phone system can maintain the speech quality.</p> |
