The phone supports multiple codecs. They simply have different priorities. The reason you always see g711 instead of g729 is because g711 has a higher priority. The modern phones (7942/7962 and above) support something like 7+ codecs.<br>
<br>-nick<br><br><div class="gmail_quote">On Tue, Jan 25, 2011 at 11:37 PM, Cisco Voip <span dir="ltr"><<a href="mailto:cisco_newbie@yahoo.com">cisco_newbie@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div>Dear Sir, <br><br>As a followup, by default SCCP phones use codec g711. So did you mean that phones automatically switched to g729 ? i totally believe your point but for my further studies can you also refer me any cisco config guide to strengthen my concept <br>
<br>Pls verify my above point<br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><div class="im">
<font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Nick Matthews <<a href="mailto:matthnick@gmail.com" target="_blank">matthnick@gmail.com</a>><br><b><span style="font-weight: bold;">To:</span></b> ccieid1ot <<a href="mailto:ccieid1ot@gmail.com" target="_blank">ccieid1ot@gmail.com</a>><br>
<b><span style="font-weight: bold;">Cc:</span></b> Cisco Voip <<a href="mailto:cisco_newbie@yahoo.com" target="_blank">cisco_newbie@yahoo.com</a>>;
<a href="mailto:cisco-voip@puck.nether.net" target="_blank">cisco-voip@puck.nether.net</a><br><b><span style="font-weight: bold;">Sent:</span></b> Wed, January 26, 2011 5:10:12 AM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [cisco-voip] Strange behaviour of CME<br>
</font><br>
</div><div><div></div><div class="h5">Transcoding is only required when there is a codec mismatch. In this case it's something like:<br><br>Phone 1:<br>g711ulaw<br>g711alaw<br>g729r8<br>g729br8<br>g722<br>...<br>etc<br>
<br>GW1 to GW2:<br>g729r8<br><br>Phone 2:<br>
same as above phone 1<br><br><br>Since g729r8 is available by all, there is no need for transcoding.<br><br>-nick<br><br><div class="gmail_quote">On Tue, Jan 25, 2011 at 2:47 PM, ccieid1ot <span dir="ltr"><<a rel="nofollow" href="mailto:ccieid1ot@gmail.com" target="_blank">ccieid1ot@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><p>The phones has built in dsp to do the transcoding.</p>
<p>duy<br>
ccie #27737 voice</p>
<p>tmobile g2</p><div><div></div><div>
<div class="gmail_quote">On Jan 25, 2011 10:03 AM, "Cisco Voip" <<a rel="nofollow" href="mailto:cisco_newbie@yahoo.com" target="_blank">cisco_newbie@yahoo.com</a>> wrote:<br>> Hi all. <br>> <br>
> I have setup the current setup in my lab<br>
> <br>> IPcommunicator-1 <br>> ------------------R1-GW-------------------R2-GW-------------IPcommunicator-2<br>> <br>> SCCP (g711) default (g729)<br>> <br>
> On R1 i simply created a dial-peer voice 2141 voip, and defined the session <br>> target and destination pattern, and also codec to be g729r8. Now when i call <br>> from IPc-1 to IPc-2, the call is successful !!<br>
> <br>> I have set this up in dynamips and 2 IPcs are infact vmware machines. What i <br>> dont understand is, why there was no need for transcoding ? the default codec <br>> between R1-GW and IPc-1 is g711, while between R1-GW and R2-GW, i set it to <br>
> g729, so isnt transcoding needed here ?<br>> <br>> <br>> <br>> <br></div>
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