| 摘要 |
<p>A telephone system which realizes voice communication by using a packet network comprises an exchange which accommodates a telephone terminal as its extension and a call processing server which processes calls on the packet network. The exchange comprises a first trunk connected to the packet network, a second trunk connected to a public network having a different protocol from that of the packet network, a monitoring module which monitors the call processing server, and when a failure occurs in the call processing server, deactivates the first trunk, and a call control module which transfers a transmission request which is made from the telephone terminal to the packet network to the second trunk when the transmission request is made and performs a detour transmission to the public network in a status where the first trunk is inactive.</p> |
