The following figure shows a basic example of how you would make a VoIP call through an ITSP. You use your analog phone (A in the figure) and the Prestige (B) changes the call into VoIP. The Prestige then sends your call through your modem or router (C) to the Internet and the ITSP’s SIP server (D). The VoIP call server forwards calls to PSTN phones (F) through a trunking gateway (E) to the PSTN network. The VoIP call server forwards calls to IP phones
(G) through the Internet.
Figure 2 Internet Telephony Service Provider Application
1.5.2 Make Calls viaIf your company has an
In this example, you use your analog phone (A in the figure) and the Prestige (B) changes the call into VoIP and sends it to the
41 | Chapter 1 Introducing the Prestige |