T.38 fax support for VoIP unlock customers

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koreyb
Quiet One
Posts: 43
Joined: 10/01/2009

T.38 fax support for VoIP unlock customers

Post by koreyb »

Hi there,

I have a unlocked VoIP freephoneline.ca number.

I use a VoIP adapter sharing a voice line with a fax machine

In the last few months, I've noticed outgoing fax calls fail, while incoming works fine. I'm assuming it's a codec used for outgoing calls that isn't compatible with t.38 fax. In testing with another service, it works fine both ways. I get this is likely not supported but could any confirmation be given that outgoing is no longer using the ulaw/alaw codec or is this something that can be changed on the server end?
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Liptonbrisk
Technical Support
Posts: 2770
Joined: 04/26/2010
SIP Device Name: Obihai 202/2182, Groundwire
Firmware Version: various
ISP Name: FTTH
Computer OS: Windows 64 bit
Router: Asuswrt-Merlin & others

Re: T.38 fax support for VoIP unlock customers

Post by Liptonbrisk »

T.38 fax protocol works, unofficially (insofar as customer support will not provide technical support for that feature), for outgoing faxes with Obihai OBi200/OBi202 ATAs and Freephoneline.
Refer to pages 31 and 32 of the PDF guide located at http://forum.fongo.com/viewtopic.php?f= ... 805#p73839. Also refer to point #4 on page 2 and also to page 45; bad jitter and packet loss can cause issues.
Even if you don't own an Obihai 200 or 300 series ATA, that general information is worthwhile reading.

You can test by faxing to a Fongo Mobile number.

I have no issues using T.38 fax protocol with Freephoneline.
Please do not send me emails; I do not work for nor represent Freephoneline or Fongo. Post questions on the forums so that others may learn from responses or assist you. Thank you. If you have an issue with your account or have a billing issue, submit a ticket here: https://support.fongo.com/hc/en-us/requests/new. Visit http://status.fongo.com/ to check FPL/Fongo service status. Freephoneline setup guides can be found at http://forum.fongo.com/viewforum.php?f=15.
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