User`s guide

ADSL/VoIP Gateway User’s Guide

VoIP

VoIP enables telephone calls to be made over an IP network.

This enables DSL Service providers to sell telephone services

over DSL to customers without the expense of providing any

extra physical connections to the consumer, or network

infrastructure in addition to their existing IP network.The DSL

Service provider can build VoIP functionality into their DSL

Modem product to create a Voice-IAD (Integrated Access

Device) system. The Voice-IAD system would typically offer

connections for the DSL line, Ethernet and/or Wireless LAN,

together with one or more analog telephone sockets to enable

the user to make telephone calls over the IP network or over the

PSTN. The decision on whether to route the call over the

telephone network or the PSTN would depend on the number

dialled and the status of the Internet connection. This feature is

known as Call Routing . The following diagram illustrates the

interfaces that would be provided on a typical Comm-Box

system:

Figure 93: Comm-Box System Interfaces

The DSL/FXO interface refers to a single connector with a

POTS filter supporting connection of DSL and PSTN to the

system. In practice, the filter may be external and an additional

FXO socket provided. FXS refers to the low-cost phone ports

(digitally connected on the board to VoIP or PSTN).