[VoiceOps] VoIP T38 Fax reliability

[Ujjval Karihaloo]

Anyone used faxback - they do T38 fax over https .... Any experience  
with them?
Their claim is it works 100% of the time



On Jan 6, 2010, at 7:37 PM, "Alex Balashov"  
<abalashov at evaristesys.com> wrote:

> On 01/06/2010 07:15 PM, Gabriel Kuri wrote:
>
>> It seems to be hit and miss, certainly not 100%, but better than
>> trying to use either PCMU or PCMA over the commodity Internet for
>> FAXing. PCMU/PCMA might work over a local private LAN with QoS  
>> enabled
>> and the jitter down to almost nothing.
>
> Agreed about T.38 vs. analog pass-through.
>
>> The biggest issue I've seen
>> with T38 is the ATA's inability to properly negotiate a Super-G3 fax
>> down to G3 or slower speeds. In our experience, you need to disable
>> the Super-G3 feature of the FAX machine to slow it down to either  
>> 14.4
>> or 9600 and disable ECM. Many of the newer FAX machines have a "VoIP
>> Compatibility" mode which essentially slows it down to 9600 and
>> disables ECM.
>
> There's been an enormous explosion of Super G3 machines in the last  
> few
> years;  asking users to disable SG3 is not really tenable.
>
> Fax over IP is one of those things that, like anything else, can be
> gotten to work passably with enough spiritual commitment.  But it's  
> just
> not worth it.  Hand the customers some resale analog lines or what  
> have
> you and be done with it.
>
> -- 
> Alex Balashov - Principal
> Evariste Systems
> Web     : http://www.evaristesys.com/
> Tel     : (+1) (678) 954-0670
> Direct  : (+1) (678) 954-0671
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