Voip Trunking Example: Pstn To Pstn Via Voip; Background Information; Configuration Details: Outgoing; Figure 97 Pstn To Pstn Example - ZyXEL Communications P-2302HW-P1 Series User Manual

P-2302HW/HWL-P1 Series User's Guide

13.9 VoIP Trunking Example: PSTN to PSTN via VoIP

This example shows how to configure a PSTN to PSTN call with a VoIP link. It also shows
how call rules can be used to automate VoIP trunking.

13.9.1 Background Information

A company has its headquarters in two different cities. The sales manager (A) from
headquarters often needs to call salespeople (D) employed at the branch office. The sales
manager often works away from the headquarters office and the sales employees often work
away from the branch office. The sales manager and the sales employees have PSTN phones
(mobile or land based). The two offices have VoIP trunking devices. The sales manager wants
to use VoIP trunking to save on calls to his sales team. The head office has a ZyXEL Device
(B) with a PSTN line (tel: 222-222-2222) connected to it. The branch office has a ZyXEL
Device (C) with a public IP address w.x.y.z. The sales employee (D) has a PSTN phone with
the number 555-555-4321.

Figure 97 PSTN to PSTN Example

The proposed solution is to configure a call rule which will allow the sales manager to call into
the headquarters via PSTN, establish a VoIP link between the two ZyXEL Devices and have
the remote peer device forward calls to the sales employees via PSTN.

13.9.2 Configuration Details: Outgoing

The ZyXEL Device (at headquarters) from which the VoIP link originates needs to have the
following configuration settings:
1 Auto attendant authentication needs to be enabled for PSTN calls coming into the
headquarters' ZyXEL Device. This ensures that no unauthorized callers use VoIP
trunking. In this example the PIN (Personal Identification Number) is set to 12345. The
settings dealing with dialing interval and a timeout period are left at default. The ZyXEL
Device waits 10 seconds (after initial connection between PSTN caller and the ZyXEL
Device) for the PSTN caller to initiate VoIP trunking by dialing another number. It waits
3 seconds between dialing digits before it determines that the entire phone number is
entered. These settings can be configured in the VoIP > Trunking > General screen.
184 Chapter 13 VoIP Trunking