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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>From what I’ve heard, fax over G711
is not a reliable solution.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><b><font size=2 color=black
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;color:windowtext;
font-weight:bold'>From:</span></font></b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:windowtext'>
asterisk-dev-bounces@lists.digium.com
[mailto:asterisk-dev-bounces@lists.digium.com] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Daniel Bichara<br>
<b><span style='font-weight:bold'>Sent:</span></b> Thursday, March 24, 2005
6:29 PM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">Asterisk
Developers Mailing List</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Asterisk-Dev] codec
renegotiation and fax [was: codec negotiationissue]</span></font><font
color=black><span style='color:windowtext'><o:p></o:p></span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><font size=3 color=black
face="Times New Roman"><span style='font-size:12.0pt'><br>
Hi All,<br>
<br>
So, if we make Asterisk start a renegotiation we could change the codec to
G.711 during a call after we detected a fax. And we will not need to implement
T.38 to make fax work between IAX or SIP devices. Cool.<br>
<br>
Daniel<br>
<br>
Michael Giagnocavo wrote: <o:p></o:p></span></font></p>
<pre style='margin-left:.5in' wrap=""><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt'>Well, if Asterisk already supports renegotiation... that's pretty cool then.<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>I'd have to try it out with the PA168 phones, which are the only decent IAX<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>devices on the market AFAIK (although some promising ones like the FarFon<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>might be soon?).<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>-Michael<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>-----Original Message-----<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>From: <a
href="mailto:asterisk-dev-bounces@lists.digium.com">asterisk-dev-bounces@lists.digium.com</a><o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>[<a href="mailto:asterisk-dev-bounces@lists.digium.com">mailto:asterisk-dev-bounces@lists.digium.com</a>] On Behalf Of Kevin P. Fleming<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>Sent: Thursday, March 24, 2005 1:03 PM<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>To: <st1:PersonName w:st="on">Asterisk Developers Mailing List</st1:PersonName><o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>Subject: Re: [Asterisk-Dev] codec negotiation issue<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>Michael Giagnocavo wrote:<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'> <o:p></o:p></span></font></pre>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt' type=cite><pre
style='margin-left:.5in' wrap=""><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>Precisely because of that - support. It's not there today, which means<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'> <o:p></o:p></span></font></pre></blockquote>
<pre style='margin-left:.5in' wrap=""><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt'>it's<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'> <o:p></o:p></span></font></pre>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt' type=cite><pre
style='margin-left:.5in' wrap=""><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>not in any devices out there today either. Also, it means it's not on any<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>providers today. So, we're talking a long time until it's universally<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>supported. However, the problem is today. And also applies to every other<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>channel, if their devices don't support renegotiation.<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'> <o:p></o:p></span></font></pre></blockquote>
<pre style='margin-left:.5in' wrap=""><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>Pretty much every SIP and IAX device you can talk to today already <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>supports renegotiation during the call. The issue right now is that <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>Asterisk never initiates it, when it has information that would allow it <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>to do so.<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>I could be wrong, but I suspect that when Asterisk is ready to start <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>doing this, it will 'just work' with all the providers and devices you <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>are referring to. The SIP and SDP protocols already fully support it, <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>and many devices already try to do it. (ever tried hitting "Conference" <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>on a Cisco 7940/7960 while in a G.729 call? it sends a re-INVITE trying <o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>to switch the call to G.711)<o:p></o:p></span></font></pre><pre
style='margin-left:.5in'><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt'>_______________________________________________<o:p></o:p></span></font></pre><pre
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