[asterisk-dev] autodetect fax on SIP channel

[Gaspar Zoltan]

Hi

I used NVFaxDetect with 1.2 for SIP. This application as far as I know
detects and decodes the fax sent in the voice channel a fax over voip
method. T.38 is a protocol that sends fax not encoded as sound, but directly
as digital data. For this is far more reliable.

Any network jitter will cause problems for nvfaxdetect and I was unable to
receive large faxes (more then 10 pages)with it. For small faxes it worked a
little bit better, but sometimes still failed.

Zoltan

-----Original Message-----
From: asterisk-dev-bounces at lists.digium.com
[mailto:asterisk-dev-bounces at lists.digium.com] On Behalf Of Alexey Borisov
Sent: Friday, July 20, 2007 9:07 AM
To: asterisk-dev at lists.digium.com
Subject: Re: [asterisk-dev] autodetect fax on SIP channel

 >Alexey Borisov wrote:

> >> Hi All.
> >> Tell me please, how-to detect fax call on SIP channel?
> >> I found some information on voip-info about app_nv_faxdetect, but it
> >> reffers me on newmantelecom site.
> >> this site is not responsible anymore ;-(.
> >> where i can take app_nv_faxdetect for asterisk 1.4? or possible any
> >> instructions, how to make it work/
> >> 
> >> thanks
> >> Alex.
> >> 
>   
>
>Hi,
>
>I think nv_faxdetect works to detect fax calls on ZAP (and mISDN), not SIP.
nv >listens 
>for the fax tones, and there are no fax tones on an incoming SIP.
>Fax over SIP is done using T.38, and I don't know how to tell it is a fax
call >at the 
>start, i.e from the SIP INVITE.
>Anyone?


Really? But in man from voip-info.org ive seen, that NVFaxDetect function 
implements fax detection just SIP and IAX channels.
here is article -> http://www.voip-info.org/wiki-NVFaxDetect 

I need it. Maybe anyone use it with aster 1.4.?

Alex.




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