Solved Fax server on bridged 3CX-systems

[Dominique_CH]

Hello,
I have to setup 2 3CX-systems in 2 locations and bridge them together. I plan to use a general unique 2- or 3-digit numbering plan with a specific number range assigned to each location..
Following question: I need to set up a fax server in each location and from my understanding and tests, the fax-server number is set by default to 88 or 888 and cannot be changed. So how should I proceed in such case ?

 

[ChrisC_3CX]

You indeed cannot change the main FAX Server extension but what you can do is add other FAX extensions that can be unique for each PBX. Also, you can have FAX sent to directly to extension emails and since your extensions will already be unique it should not be a problem.

 

[Dominique_CH]

I don't get your point: of course, I can add some other fax extension on the other site, but what if I have a fax-server on each site which, in my case, would have the same extension number assigned by the system ?
I imagine one solution would be using a prefix for the fax only, but there might be some better idea.

 

[ChrisC_3CX]

@DrNo

You're right, you would indeed have to use a prefix for this and just strip it on the Outbound rule. I can't think of another way to do this.

EDIT: To be honest we have not tested this specific scenario so I can't guarantee it will function as expected. We'll look into it and come back to you.

 

[ChrisC_3CX]

To follow up on my previous reply, this can indeed be done with the prefix, though do note that you will have to enable "Re-invites" on the SIP Trunk of the PBX that originally receives the FAX call.

Do bear in mind that enabling re-invites may cause other issues depending on the call flows and the provider, so you might want to consider just having FAX sent to email addresses directly from the first PBX instead.

 

[Dominique_CH]

Ok, and how would you send out faxes from location A (having a fax-server configured) to email on location B?

 

[ChrisC_3CX]

Sending FAX via 3CX would mean that you would have to have an FXS gateway with a FAX machine connected to it. This would be configured on PBX A and outbound FAX would have to go through the 3CX Bridge to be then routed out from a SIP Trunk. I do have to mention though that we have not tested this specific scenario so we cannot guarantee it will work correctly.

 

[Dominique_CH]

What exactly do you mean by "routed out from a SIP Trunk"? Coming through the bridge, the fax doesn't use any SIP-trunk in such scenario. So, if I understand you correctly, the fax from PBX A would have to be routed through the bridge to PBX B, and from there out via a SIP-trunk to the PBX B's fax server and from there to the configured email-address? Can't the fax be routed directly from the bridge to PBX B's fax server's internal extension?

 

[ChrisC_3CX]

There seems to be a misunderstanding.

My previous reply refers to sending FAX only.

For receiving FAX see below:

Assumptions
-----------------
PBX A is connected to PBX B via the 3CX Bridge
PBX A has SIP Trunks configured whereas PBX B does not
-----------------

What you require is that FAX coming in to PBX A via the SIP Trunk are routed via the bridge to PBX B's FAX Server and therefore sent to an email address. Since setting this up is not that straightforward and may cause issues depending on the situation, and since you only require that FAX is sent via email, what I recommend is the following:

1. Create a "dummy" extension on PBX A to be solemnly used for FAX which would normally be destined for PBX B.
2. Configure it with the email address you would've set on PBX's B FAX Server
3. Still on PBX A, route the DID FAX to the dummy extension's email:


Essentially, PBX B will not be involved in the above configuration at all.

 

[Dominique_CH]

Hello Chris,
Thanks for this last reply which is an excellent workaround

 

[ChrisC_3CX]

You're very welcome!

Please feel free to start a new thread should you require anything else!