| 摘要 |
<p>An IP telephone exchange connects an IP telephone terminal and a non-IP telephone terminal to enable conversation between therebetween. The IP telephone exchange includes a communication control section, a voice channel, a control channel and a voice channel management section. The communication control section conducts data communications with the IP and non-IP telephone terminals. The voice channel interconverts between non-IP voice data and IP voice data. The control channel communicates a call control signal with the IP and non-IP telephone terminals. The voice channel management section detects presence or absence of an available voice channel when communication connection is established between the IP and non-IP telephone terminals based on the call control signal. The voice channel management section notifies a calling telephone terminal and a called telephone terminal that no available voice channel exists, if the voice channel management section detects no available voice channel.</p> |
