We can connect the VG3XE-2S/2 gateway (a gateway with 2FXO and 2FXS ports) and AX210 IP PBX without the registration to make the functions below available:

1. IP extension and the analog extension on FXS port can call each other;
2. IP extension can call out via the FXO port;
3. The analog extension on FXS port can call out via FXO port;
4. When a call comes in, it will be sent to the IVR of AX210.

In this example, the IP address of AX210 is 192.168.1.9, and the extensions are registered on AX210 with numbers 8xxx, for instance, 8001, 8002. The IP address of VG3XE-2S/2O gateway is 192.168.1.3, and the FXS port 1 is connected to an analog telephone, setting the phone number as 8001; FXO port 1 connects to a PSTN line.
The detailed settings are here:
First of all, we need to create a Line Provider in PBX General as SIP Direct:

When the Real Status shows as below, it proves that the connection between VG3XE-2S/2O and AX210 is ok.

Then we can make the specific settings.
1. IP extension and the analog extension on FXS port can call each other;
Because that we haven’t registered the FXS port, we need to write the Routing Table in VG3XE-2S/2O gateway to make sure they can call each other. As mentioned before, the phone number of FXS port 1 is 8000:

So the Routing table here means that the call of 8000 will be sent to FXS port 1, and the callee number which begins with 8 from FXS port 1 will be sent to PBX220.

2. IP extension can call out via the FXO port;
This we need to create an Outbound Route on PBX220 and write the Routing Table on VG3XE.
This is the Outbound Route on AX210, it means the calls will go out via the line named gateway2.

This is the routing table :

3. The analog extension on FXS port can call out via FXO port;
The rule marked on the picture below can make the FXS port call out via FXO port.

4. When a call comes in, it will be sent to the IVR of AX210.
We can create an IVR on AX220 first, then set it as the call in number.


If there is only one trunk available, then we have no need to create an inbound route because the default can work fine. But if there are more than one trunk, we need to create an inbound route to ensure the incoming calls  matching well with the trunk we created.
Here is the Inbound Route:

That is all work we need to do to make the gateway and AX IP PBX work together.