Interconnect Two or More Extension Lines with FXS Gateways
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 second one popular application and related configurations are described.


In this scenario, two or more extension lines located at different sites need to be interconnected through IP network, without any SIP server or IP-PBX.

In this diagram, each of the FXS gateways is installed with the FXS ports connected with analog phones while the WAN port is connected 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

On Routing > Routing Table page, input the routing rules for directing calls from extension lines 8000-8003 to IP address, as follows:

Configuration on Gateway B

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

Dialing Method

For making calls from one site (e.g. extension 8001) to an extension on the remote site (e.g. extension8004), the user of extension 8001picks up the phone and dials8004, and then call will be set up between 8001 and 8004.

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