ZyXEL Communications P-2602HWLNI User Manual

 Chapter 12 VoIP Trunking

P-2602HWLNI User’s Guide

This example shows how to configure VoIP to PSTN trunking to save on long distance calls.

A company has its headquarters in city A and a branch office in city B. The headquarters often 
needs to call salespeople employed at the branch office. The sales employees often work away 
from the office and have PSTN phones (mobile or land based). The two offices have VoIP 
trunking devices and want to use VoIP trunking to save on calls from the headquarters to their 
sales team. The head office has a public IP address a.b.c.d and the branch office has a public 
IP address w.x.y.z.

Figure 126   VoIP to PSTN Example

The proposed solution is to establish a peer-to-peer call between the two ZyXEL Devices and 
have the branch office ZyXEL Device forward calls to the sales team members via PSTN.

The ZyXEL Device (at headquarters) from which the call originates needs to have the 
following configuration settings:

1 Speed dial entries need to be set up for the numbers headquarters wants to call. The 

destination field of these entries is the IP address of the branch office ZyXEL Device. 
This must be a non-proxy IP address. The numbers are the phone numbers of the sales 
team members. This can be configured in the VoIP > Phone Book > Speed Dial screen.