[asterisk-users] Asterisk 1.4 Fax

[Rob Hillis]

I think perhaps you are the exception rather than the rule.

Maybe you were able to engineer your network so that fax works without
any of the FoIP protocols - good luck to you if you have.  For /most/
people, it's unlikely they would have sufficient control over their WAN
segment to ensure that it is sufficiently fast and reliable enough for
fax to work reliably.

In any case, why on earth would you attempt to re-invent the wheel? 
T.38 is not only considerably more reliable and robust, it's nowhere
/near/ as bandwidth intensive as G711.

The original question was regarding using IAXmodem and Hylafax to
receive faxes over a SIP connection.  Given that T.38 can not work in
this situation, the simple answer is that it /isn't/ the best solution.


Jonn R Taylor wrote:
>
> NOT true and I have proven that for the last year.
>
>  
>
> Jonn
>
>  
>
> ------------------------------------------------------------------------
>
> *From:* asterisk-users-bounces at lists.digium.com
> [mailto:asterisk-users-bounces at lists.digium.com] *On Behalf Of *Rob Hillis
> *Sent:* Tuesday, January 01, 2008 4:13 PM
> *To:* Asterisk Users Mailing List - Non-Commercial Discussion
> *Subject:* Re: [asterisk-users] Asterisk 1.4 Fax
>
>  
>
> I'd say "consider yourself very lucky".  I know I did some testing
> here some time ago with faxing over VoIP.
>
>     * One extension to another over G711a with both extensions on the
>       same LAN - worked 95% of the time
>     * One extension on my Asterisk server to an Extension on a
>       friend's Asterisk server using G711a via IAX - 95% failure
>       rate.  Both of us awere on the same ISP and had ping times of
>       ~40ms between us.
>
> However, in a live environment, I convert a PSTN call to a t.38
> encoded call and can send the fax just about anywhere I damn well want
> (where the remote end supports t.38) with a 95% success rate.
>
> t.38 is the key to successful faxing over a VoIP network.  Without it,
> you're begging for trouble.
>
>
> Doug Lytle wrote:
>
> Jonn R Taylor wrote:
>   
>> If I had ANY failed faxes I would here about it. Iaxmodem creates a log of its own, so when I get a connection that fails hylafax sends the failure to me. One of the things that I found is you need to add nojitterbuffer to the iaxmodem config file, 
>>     
>  
> Really?  I'll have to do some testing, I've never tried since I've read 
> you can't.
>  
> Doug
>  
>  
>   
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>
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