Interconnect Two PBXs with FXO Gateways
Update Time:2018-04-18 13:15:15 Browse Times:2046 Amount Downloads:689
New Rock’s SIP based VoIP gateways (MX series gateways) with FXS and FXO ports support peer-to-peer mode which has many applications in deploying enterprise multi-site telephone communication. In this application note, three popular applications and their related configurations are described:
-  Interconnect two PBXs at separate sites through IP network with FXO gateways
-  Interconnect two or more extension lines at separate sites through IP network with FXS gateways
-  Expanding PBX extensions to remote sites through IP network
In this application note, the first one popular application and related configurations are described.


In this scenario, two PBXs located at different sites need to be interconnected through IP network, and spared extension lines are used to connect to the gateway.

In this diagram, each of the FXO gateways is installed with the FXO ports connecting to the extension ports of the PBX while the WAN port connecting to the router in the local office. Both gateways are interconnected over the IP network with SIP protocol in peer-to-peer mode for call setup.
Note: A static public IP address is required if the IP network is Internet.

Configuration on Gateway A

1. On Routing > Routing Table page, setup the routing rules for directing call from FXO port to IP and vice versa, as follows:

2. On the > Trunk>Feature, select Second stage dialing in the inbound handle field, and select Dialing tone.

Configuration on Gateway B

1. On Routing > Routing Table page, do the similar routing as follows.

2. On the Line > Trunk, same as we did on gateway A.

Dialing Method

For making calls from one site (e.g. extension 201)to an extension on the remote site (e.g. extension 301), the user of extension 201 picks up the phone and dials the number for the local extension port which connects to the gateway (202 in this example), and then dials301 after hearing the second stage dial tone from the local gateway.

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