| 摘要 |
A telephone system is disclosed establishing a link over a packet-switched-network, such as the Internet, between two telephone interfaces by exchanging network addresses. The addresses can include ATM addresses to allow a virtual connection to be established between the interfaces. The interfaces exchange speech data packets of speech signals from a called party telephone and a calling party telephone over the network. An interface converts the speech signals of the parties into the speech data packets. The system dynamically allocates network and interface resources to complete the telephone call transaction. The system provides a number of enhanced calling services not normally available to PSTN subscribers including: message-delivery, call-back, call-screening, network-camp-on, call-back-from-queue, find-me, meet-me-pager, call-forwarding, call-interrupt, call-waiting, business-dialing, automatic-call-distribution, virtual-automatic-call-distribution, speed-dial, call-transfer, conference-calling and network-administration. Echo cancellation is used to eliminate echoes caused by PSTN circuits associated with the telephones. Silence detection is used to improve network efficiency by not sending packets when the parties are not speaking. The delay in the packet-switched-network is used to adjust the size of sound segments formed into a packet. The interfaces allow the system to provide end points in a packet-switched network that manage a telephone call over the packet switched network.
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