3CX + Patton 4552 == massive noise

[zigaj]

Hi, Everyone!

I've installed Patton 4552 on my ISDN BRI line, wiht 3CX 9 (last build) as the PBX.
The Patton was configured via 3CX, and is presently set to use 711a pass-through. (no difference with 711u)
The analogue fax machine (Samsung MFC) is on a SPA-2102, configured for fax as per 3CX instructions for SPA 3102.

I can fax between 2 fax machines on different SPAs in the house. I can (in part; some problems with our telco) receive and send faxes over my VOIP lines - however this is transmitted as pass-thru.

The Patton setup works in part; as soon as the fax tone detection kicks in, the "hissing" noise becomes overwhelming and drains everything else out.

Any hints?

Regards,

Ziga

 

[mfm]

Hi,

Is this when your on a call on another line or when does it happen?

 

[zigaj]

Hi!

Figured it out on my own - when I moved the Patton to bypass the fax via a-law, it worked.
Apparently, t38 doesn't quite work between Patton 4552 and SPA 2102.

Regards,

Ziga