How to use freepbx and ATA router to work with physical fax?


My project need to use freepbx and ATA router to work with physical fax machine and I understand it is very hard to make the connection because of compatibility issue.

I just wondering is there any resources or tutorials to teach me how to set it up successfully and I can buy the same type fax machine and ATA router to do the same way.



The FreePBX Wiki has a lot of information about using ATAs, but how you are planning on using the FAX machine will drive a lot of your decisions. Instead of asking an open-ended question, perhaps you can ask something specific that doesn’t take 20-questions to get to what you really want.

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I totally understand and agree with what you said. I have learned about how to using ATAs but the physical fax machine, as like you said, has lots of changeable factors to work with freepbx. There are not so much open resource to introduce how to setup together.

Chris is the most knowledgeable freepbx youtuber in this area and I have learned all the skills from him. Also, he doesn’t recommend to use freepbx to work with physical fax but my supervisor insist on the feature.

That is the reason why I want to looking for someone who may have this experience before and recommend me the compatible version of ATA and Fax machine so that I can build up the connection successfully.

As newbie in freepbx area, hope you can understand my concerns.



The problem you’re going to run into is that there’s no set configuraiton that “just works”. There’s a lot of local variables, as well as mechanisms within the field that you have to deal with.

For example, how are you going to use Asterisk/FreePBX in the mix? Are you using it to send or receive faxes? If you are using an external FAX machine, are you set on using a local ATA to interface to the machine, or are you willing to use a USB connected device as a printer? How are you going to connect the FAX machine to the larger telephone network? Are you going to use T-38 over a VOIP line or are you using a telephone line? Is the ATA to connect the phone line to your FAX or are you setting the ATA up to work between your FAX and Asterisk?

Every one of these answers begs a couple more questions, and all of them have local limitations and effects that having a “working” configuration may not take into account.

Having wrestled with this myself over several years, I’ve decided that letting an external FAX server (my ITSP, in this case) handle all of the FAX needs for my supported organizations and just work with FAXes through email.

Of course, your mileage may vary.

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Unless you have a very unusual workflow, IMO a physical fax machine no longer makes sense, especially one that you have not yet acquired.

For receiving faxes:

  1. Unreliable – can run out of paper, be busy, etc.
  2. Insecure – people walking by the machine can see stuff they shouldn’t.
  3. Inaccessible – if you receive an important fax while out, you can’t view it until return to the office.
  4. If you need to save or forward the document, it must be rescanned, resulting in a generation loss.
  5. Difficult to search content of document.
  6. Wastes trees.

Sending faxes:

Most faxed documents were either created by the author on a computer, or originally received by web, email, or fax, then edited and/or signed. Get software to do this electronically.

If a paper document was delivered personally or by post, it’s likely something important that should be scanned anyway.

If it’s an internally created paper document, there is usually a better way to enter the data.

If you’re concerned about HIPAA or other regulations, there are numerous compliant services, e.g.

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I just need the most simple function on Fax machine. Sending and receiving feature.

Connect an OBI directly to a SIP provider, get a T38 DID by preference, No PBX needed.

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Ok, I have realized this is a very special area and I don’t have so much related background. I will stop working on that.

Really appreciate it you words and suggestions, I will do further researches to find any possible ways.

Use a fax T.38 provider like and follow their directions. Good support too.


We wrote a guide for this recently, it’s was written with our service in mind, but should be a good starting point for configuring fax with FreePBX and an ATA…

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That is very helpful, really appreciate it. From the tutorial, I have realized the problem is I am using chan_sip extension not PJSIP. Thank you for your instruction.

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