Fax Configuration

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Asterisk Users 5 Comments

What is the best way for me to setup Fax Capability with VOIP only.

I have a Asterisk Server hosted on the internet without a modem. I’m using Flowroute, which is working awesome, for VOIP calls.

I only have a SIP Phone at home and two Printer/Scanner/Fax Printers.

I’m not sure which Fax Addons or Extensions I should use for Asterisk.
I’d like it to Self Detect on any line.

I also am not sure what or how I can connect a Network Only Printer/Scanner/Fax Machine at home to it. It has a Telephone Jack but I’m only using VOIP.

I’m pretty advanced with Asterisk now and can figure things out..I would just like some advice and direction before I get started.

Oh, one more thing. Is there any way to Route the Faxes to different folders (extensions) because I have End Users with Phone + Extensions when you call in.

5 thoughts on - Fax Configuration

  • You can use T.38, perhaps, if your VoIP provider supports it and you can get it working. But unless you need faxes to go through the telephony system (i.e. you have fax machines hooked up to FXS ports) I’d recommend using an on-line fax service such as Mainpine’s instead of trying to do fax over VoIP.

    Fax over internet-strewn SIP generally isn’t going to work very well.

    So on your MFP you’ll scan it instead of using the system’s “fax”
    capability, and then fax it through the online service.



  • Roy,

    Many will say that it all depends on your provider supporting T.38, and that you should forget it otherwise.

    My practical experience shows otherwise. I am able to receive faxes on SIP lines pretty reliably with no T.38 support. The biggest issue for me is CED tones detection. If CED is detected then fax reception goes on with no problems. I use this setup with both Asterisk receiving a fax and then e-mailing it to me as a PDF attachment and with a call being forwarded to a fax machine extension which in turn is connected to a Motorola ATA over another SIP connection.

    I use FreePBX to set all that up as they provide pretty easy fax setup.


  • This has been my experience also (with fax reception). Incoming faxes work for us nearly 100% of the time.

    I have not messed with fax sending and so cannot comment on that.

    Kind Regards, Chris

  • I got it working so thought I’d follow up!

    Here is what I had to do… I’m using Actuate 11 and had res_fax support already I had to download, compile, and install res_fax_digium I had to order a Free Fax License from digium for 1 channel I had to change faxdetect=yes to faxdetect=cng in sip.conf or I would get an error… I had to change my dialplan to Answer, Wait(2) before the Dial command. I had to add a extension for fax or I’d get an error fax extension not found…

    I created a fax-in dialplan and fax-in.pl to email me a PDF
    I created a fax-out dialplan and fax-out.pl to send faxes

    I created a Free account at googles hellofax.com to test receiving a fax-in. I created a Free account at PopFax.com to test sending a fax-out.

    It works even though my VOIP Provider, Flowroute, doesn’t support T.38 Fax. I just had to make sure I Answer and Wait(2) to detect the fax tone.

    If anyone wants more details let me know.

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