well, my experience with T.38 is that we switched it off within our network and now use passthrough instead :P.<br><br>the reason: <br><ul><li>new fax machines that defaults to v.34 and on some you cannot disable SG3 at all... just imagine what pain it is to produce a how to disable V.34 manual for every damn fax machine<br>
</li><li>a variety of T.30 <> T.38 mapping issues, broken GWs/ATAs that don't do a correct encoding/decoding expectantly when it comes to a terminating fax server that doesn't send a proper EOP... God save our souls...<br>
</li><li>our network has very low jitter - up to 40 ms , so passthrough works perfect</li><li>bandwidth become cheap :=)</li><li>and ... don't even remember any fax issues after shutdown T.38</li></ul>i could go with the list... but i suppose you have better things to do :P<br>
<br><br>T.<br><br><div class="gmail_quote">On Thu, Oct 22, 2009 at 9:29 PM, Gabriel Kuri <span dir="ltr"><<a href="mailto:gkuri@ieee.org">gkuri@ieee.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
AFAIK T.38 v2 supports a max speed of 14.4 anyhow, so that's the max<br>
speed you'll ever see in the SDP. T.38 v3 supposedly supports v.34<br>
speeds, however no one that I've seen has implemented it yet - not sure<br>
it's even an official standard?<br>
<br>
Yes, in my experience, v.34 capable FAXes do not properly negotiate down<br>
to 14.4 speeds, we've always had to disable v.34 (or whatever the option<br>
is called on your particular make/model to force it down to 14.4 or<br>
slower speeds). We use the Cisco/Linksys ATAs - I've heard there's<br>
better ATAs out there that properly negotiate the FAX down to 14.4 on<br>
the T.30 side of the connection, but never had a chance to play with them.<br>
<br>
I'd certainly be interested to hear anyone's experience with T.38<br>
reliability and various combinations of FAX machines and make/model of ATAs.<br>
<br>
Gabe<br>
<div class="im"><br>
Kristian Kielhofner wrote:<br>
> Gabe,<br>
><br>
> I don't think any of them are plus the T.38 SDP tells me the bitrate<br>
> is 14400, certainly not V.34 speed.<br>
><br>
> Are you saying the machine even trying to negotiate V.34 poses a problem?<br>
><br>
> On Thu, Oct 22, 2009 at 2:16 PM, Gabriel Kuri <<a href="mailto:gkuri@ieee.org">gkuri@ieee.org</a>> wrote:<br>
>> Out of curiosity, is it a Super G3 (ie v.34) capable FAX? We've had<br>
>> nothing but intermittent problems with Super G3 FAXes over T.38, unless<br>
>> v.34 is strictly turned off on the machine.<br>
>><br>
>> Gabe<br>
>><br>
><br>
<br>
<br>
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