| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an IP telephone switching device and an IP telephone terminal which are easy to handle in an IP telephone switching system where non-IP telephones and IP telephones are intermingled, even if voice channels for calls between non-IP telephones and IP telephones run short of. <P>SOLUTION: The IP telephone switching device detects existence of available voice channels, when communication connection is established between an IP telephone terminal and a non-IP telephone terminal. The device notifies a lack of voice channels to a calling telephone terminal and a called telephone terminal if an available voice channel is not detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
