| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a communication system for inexpensive IP telephone equipment, which avoids communication tapping without depending upon encryption techniques. <P>SOLUTION: First or second IP telephone equipment determines a port number of a transport layer for use in data forwarding processing by packets and informs the other party of telephone conversations of the determined port number of the transport layer, and the other party of telephone conversation informed of the port number of the transport layer changes a port number of a transport layer for packet communication, and the port number of the transport layer is changed at least once during telephone conversations. <P>COPYRIGHT: (C)2004,JPO</p> |
