| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect deterioration in the quality of communication with a voice communication apparatus of the other party when the method of encryption and decryption of voice data is changed after a predetermined time in a voice communication system in which voice data is encrypted and the encrypted voice data is transmitted and received to/from the voice communication apparatus of the other party. <P>SOLUTION: The voice communication system includes a first voice communication apparatus and a second voice communication apparatus. The first voice communication apparatus and the second voice communication apparatus receive encrypted voice data containing a predetermined bit stream from the voice communication apparatus of the other party, and decrypt the encrypted voice data. The first voice communication apparatus reports a time when the method of encryption and decryption of voice data should be changed to the second voice communication apparatus. If a predetermined bit stream is not reproduced in decrypting voice data received from the second voice communication apparatus after the time, based on the method after the change, the first voice communication apparatus determines that the communication quality deteriorates. <P>COPYRIGHT: (C)2011,JPO&INPIT |
