| 摘要 |
PROBLEM TO BE SOLVED: To enable switchover to encryption communication between IP telephones having an encryption function without passing through a call control server.SOLUTION: An IP telephone includes: an audible sound transmitter for outputting a preset encryption communication request sound to an IP telephone on the reception side for encryption communication; an audible sound detector for monitoring the reception of the encryption communication request sound and outputting a switchover signal on detecting the encryption communication request sound; and an encryption processing unit for switching a circuit on receiving from a user an encryption request indicative of switchover to the encryption communication and the switchover signal, so that a sound caused by encryption key data is not output from a receiver when an identification signal and an encryption key are received as voice data, to share the encryption key and perform encryption processing using the shared encryption key. |
