ZyXEL Communications P-2602HWLNI, User Manual, Page: 219 / 496

Chapter 12 VoIP Trunking
P-2602HWLNI User’s Guide
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12.8 VoIP Trunking Example: VoIP to PSTN
This example shows how to configure VoIP to PSTN trunking to save on long distance calls.
12.8.1 Background Information
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.
12.8.2 Configuration Details: Outgoing
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.