Configuring Inter-PBX Connection Between Grandstream UCM 6104 Using IAX Trunks

As the title said,

Right now I'm going to show you how to create inter PABX connection.
As for now, we have two HQ offices using UCM6104 right now, one in Jakarta and the other in Bangkok.
While we're miles by distance, we still have VPN connection.

And here's how to do it.

Firstly,
Let's assume we have two PABX with these IP Address as this is my configuration at office:
JKT Office : 192.168.53.10
BKK Office : 192.168.10.113

Both are using the same GXP6104 model. And here we're going to make the IAX trunk for both of them.

Step 1 : Making IAX Trunk in Both, JKT and BKK PBX
For those who doesn't know where VoIP Trunk, it is located under PBX > Basic / Call Routes > VoIP Trunks Sub Menu here, I started with the one in BKK first. Click on the Create New IAX Trunk and proceed as below.
- Provider Name : This is just a name, I name it ConnectJKT
- Host Name : Add the other side's PBX IP Address, this one I put the JKT IP Address, 192.168.53.10

And the next will be configuring the other side as well, the one in JKT

- Provider Name : Same as above, I name it ConnectBKK

- Host Name : IP of BKK PBX, 192.168.10.113

If you can ping the one in JKT from BKK and vice-versa, then it's already connected.

We just need to put an outbound and inbound rules for the call to be able to call each other.

Step 2 : Making an Inbound and Outbound Call

This menu also located in PBX > Basic/Call Routes > Inbound Rules and PBX > Basic/Call Routes > Outbound Rules.

Now I'm setting the Inbound Rules first in BKK. Select the Trunks on Dropdown menu first, then click on Create New Inbound Rules and proceed as below.

- Trunks : IAX Trunks, the one you've recently created.

- DID Patterns : Here is what we have to input on the IP Phone before making a call, I made it 61xxx. So when users call with 61 followed by extension number, let's say 116, so it will make it 61116, it will be forwarded through this trunks (IAX Trunks - ConnectJKT).

- Privilege Level : Internal (Used for Inter PBX Connection)

- Default Destination : As we want it to call another Extension using pattern, we set it DID

- Strip : We want to delete the 61 prefix so the call could make it to the next destination so we strip 2 numbers before the extension. We fill it with "2".

- Prepend : None

- Prepend Trunk Name : None

- Dial Trunk : Unchecked

- DID Destination : Extension

And we continue in configuring the outbound rules of the JKT side now.

- Calling Rule Name : It can be anything, possibly use the nearest to what it should do, I name it ConnectBKK

- Pattern : Again, this one should be similar to the one which has been set in the BKK side. I set it to 61xxx

- Password : I don't set any password for it.

- Call Duration Limit : I don't set any too here.

- Privilege Level : Internal (Default for inter PBX Connection)

- Enable Filter on Source Caller ID : None

- Use Trunk : Use the IAX Trunk that has been created before

And you're done. 

You will be able to call to BKK extension using 61 as prefix first followed by the extension number.

For example, I want to call someone with extension 105 in BKK, I should input 61105 on my IP Phone.

And you must set the outbound route for BKK and inbound route for JKT if you want to be able to call from Bangkok to Jakarta.

Thank you for reading this

APZ