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Analog FAX Machine on SPA 2101 or PAP2T in Europe (Austria)


I try to setup an ATA to use my analog FAX machine over VoIP.

Situation:  Brother 7225N FAX machine, PAP2T oder SPA 2101, Ethernet, 3CX PBX - software, Patton 4552 Gateway to ISDN public network.

Result: Phone works, FAX receiving works with SPA 2101, but not with PAP2T, sending a FAX fails. The both FAX machines sending the common piep tones against each other, but no communication is establishes.

I try out several settings, I found along the documentation and some other forums, nothing helps.

Is there any body outside, who has setup a similar system which works? And if so, whats the key settings?

THANKS for helping.

With best regards




It is normal that the fax fail when you use PAP2T device, because it doesn't support the T.38 protocol which is supported by the SPA2102. From time to time it work when you set the parameters shown in the picture that i attached to my current post and most probably will work but not always. Try it and see what the result will be. Another thing, assure that the speed of your fax machine is betwin 7200-14400 bit/sec.

Best Regards,

Bozhidar Nedyalkov


I know, that the PAP2T should fail, so I buy a SPA2102, but its the same thing, the both machines are beeping against each other, but don't understand.

Best regards



so that is what I found out:

I use the 3CX PBX system which includes a fax server. I also get software from 3CX for installing a fax device on some computer in my locale net.

I try to send a fax message from one of my machines to the fax server and I try it also the other way round. I also send a fax message from this machine to some other analog fax station over ISDN and my Patton SN4552 gatway. No problems.

I try to send an analog FAX from my Brother 7225N via SPA2102 to the 3CX fax server and vice versa, both fails. I try out a lot of different settings at the SPA2102, nothing helps. This transmission uses only the local network, firewalls and similar should not be a problem.

So I know, that the ISDN gateway isn't involved and I don't have to fiddle around with it. Outbound FAXes were received and were sent without any problem from the 3CX fax server using the T.38 protocol.

I don't understand, why faxing is such a problem using T.38. Is there any alternative solution?

Can anybody tell me a working setting for the SPA2102??

Can anybody tell me a working device?

With best regards


Dear Gerhard;

I suggest you contact the Small Business Support Center, contact info in on the suport area of the main page of the community.