| 摘要 |
<p>PURPOSE:To prevent communication resourses from being wasted by automatically inspecting, finding and restoring that a call established in a public packet switching network via a private packet switching network is allowed to stand uselessly due to the abnormality of a calling side or an incoming side PT. CONSTITUTION:The call established in the public packet switching network via the titled equipment is stored and updated in a memory circuit 414 per logical channel. Validity at the packet level of the established call is verified at every logical channel, and such decision is made whether the logical channel is effectively used or allowed to stand uselessly. If the channel is judged to be invalid, the call of the logical channel is automatically cut and the operation is restored.</p> |
