Voice Over IP

PATH BETWEEN AN INTERNET USER AND THE INTERNET

Figure 5-1 shows a typical configuration employed between the user customer premises equipment and an internet. The user employs a conventional V Series modem to modulate the analog signals on the local loop to the local telephone office. At the telephone office, the analog signals are digitized in some type of T1 frame (T1, T3, etc.), and sent through the telephone digital backbone to a designated ISP. The telephone company performs the analog-to-digital (A/D) and digital-to-analog (D/A) conversion operations. Therefore, the interface between the telephone system and the Internet Service Provider (ISP) node is digital if the telco backbone is used.

Figure 5-1. Connecting to the Internet Service ...