[asterisk-users] iaxmodem - fax tone?

[Yuan LIU]

>From: "Bill Gibbs" <bgibbs at edurotech.com>
>Date: Fri, 16 Feb 2007 15:55:13 -0500
>
>I am testing out hylafax and iaxmodem.  Submitting jobs to the hylafax
>server and having it then dial using iaxmodem is working fine.
>
>Hylafax server is talking to my  Asterisk box that has a Sangoma A101 in
>it via iaxmodem via an IAX channel using ulaw.
>
>A call coming into a certain test DID comes into the Sangoma A101 then
>it goes to another box via IAX ulaw that uses the rxfax app to capture
>the fax.  I am using rxfax right now because I am just starting to test
>hylafax.
>
>Normal faxes into my test DID work fine so I know it's not the Sangoma
>or rxfax app or communication between those 2 servers.  I notice the
>Sangoma detects incoming fax tones for these faxes.
>
>However, if I send the fax via iaxmodem, I notice the Sangoma sends the
>call out via my trunk group that turns off the echo cancellation
>(Because I am using a group I setup to do that, there it's surprise
>there) but when it comes back in, the Sangoma is not turning off echo
>cancellation.  The end result is rxfax gets the tiff image, but then the
>call just hangs up and the pdf is never created and sent.  The Tiff
>image appears to be complete however but the call just hangs up after
>that.

I don't have experience with iaxmodem (although your posting just gave me 
great confidence that I could use it).  But you missed one piece of info: 
when "normal" FAX' send to your test DID, does Sangoma turn off echo 
cancellation on that channel?  This would be a useful test to confirm your 
theory that echo cancellation is causing the problem.

Another piece of useful information would be, when you say "when it comes 
back in", do you mean you are using iaxmodem to dial another channel in the 
trunk group it dials out, and that channel uses iaxmodem on the same server 
to receive the FAX call?

Yet another important - and easy - test would be the one you haven't done: 
send a FAX via the trunk to an alalogue FAX.  Or may be you have?  I mean, 
send a FAX via Sangoma to an alalogue line to receive the FAX.  If you are 
concerned about spamming other people's FAX machine, you can even set up 
eFAX for free in one minute, and send the test FAX to yourself. (But get to 
wonder how your office FAX is connected.:-)

Yuan Liu

>I think the problem is due to the Sangoma not detecting the fax tones.
>Am I missing a setting with iaxmodem or hylafax?
>
>To recap:
>
>Test DID works fine with normal analog and other fax via ATA adapters so
>I think I can safely rule out a misconfiguration there
>
>Iaxmodem registered, hylafax clearly sends the fax via it as I see it
>coming back in and the tiff created using rxfax
>
>The problem appears to be coming back - echo cancellation not being
>turned off.
>
>Unfortunately like many of us, I don't have a test PRI server I can play
>with so I have to do this after hours.  I will be turning off echo
>cancellation late at night and seeing if that solves the problem but
>wanted to pose this question to the list.
>
>I have _not_ tested it to an outside analog fax yet via
>hylafax/iaxmodem.
>
>Bill