Is there a way to configure Fax extension to work via STUN?

[comp4all]

Hi

I'm working with the latest 3cx hosted system.
I have a customer that is using a fax machine, I installed Grandstream HT802 and connected the fax machine to the HT802.
I configured the fax machine to work with T.38 and all configurations are setup to support it.

i couldn't find a way to configure the fax extension with STUN, and I keep getting the WAN Blocked message. i know that in the extension tabs you have the option to enable remote extensions.

Any ideas on how I can get this running?

TIA

 

[Kevin@voxtelesys]

3CX only supports ATA's via DECT/FXS as a LAN configuration, you would have to install an SBC on site.

Or you can just connect the ATA to an extension in the PBX with the PBX IP (STATIC) and extensions credentials. We also have customers that just register the ATA separate from the 3CX and we point only the fax number(s) to that reg.

 

[comp4all]

3CX only supports ATA's via DECT/FXS as a LAN configuration, you would have to install an SBC on site.

Or you can just connect the ATA to an extension in the PBX with the PBX IP (STATIC) and extensions credentials. We also have customers that just register the ATA separate from the 3CX and we point only the fax number(s) to that reg.

Thank you Kevin for your quick response
I tried to do that but the outgoing faxes weren't working.
the incoming always worked.

 

[Kevin@voxtelesys]

Can you slow down your BAUD rate on the fax machine?
Are you testing to a local number? Try HPs test line: 888-473-2963

Can you get your carrier to open a trace and let you know what they see in the fax re-invite?

Note
*Incoming faxes may be supported but your carrier my not be supporting G711 outbound
*When going over the extension it will use G711 and not T38.

 

[JohnS_3CX]

We also support FXS gateways over SBC now. For example:



So you can connect it via SBC and choose fax transmission in T.38 from the same page you see above

 

[comp4all]

We also support FXS gateways over SBC now. For example:

View attachment 19673

So you can connect it via SBC and choose fax transmission in T.38 from the same page you see above

Thank you John.

I did that but for some reason I Still get the WAN Blocked for that extension.

 

[JohnS_3CX]

Is that extension perhaps registered elsewhere, on a forgotten device or something?

SBC extensions are not affected by WAN restrictions

 

[comp4all]

Is that extension perhaps registered elsewhere, on a forgotten device or something?

SBC extensions are not affected by WAN restrictions

 

[comp4all]

No,
it's configured to the SBC.

 

[JohnS_3CX]

I would factory reset the HT801 and then follow the guide to update its firmware and reprovision it:
https://www.3cx.com/voip-gateways/grandstream-ht-fxs/

Then if needed you can run a capture and see what IP the devices tries to register from.