<HTML dir=ltr><HEAD><TITLE>Re: [cisco-voip] Echo on IP Phones through PRI</TITLE>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>try to increase your output attenuation ( you set it to -3 which is a gain of 3) play with this vlaue but with positive values not negative and it will do it for you, the echo problem is mainly affected by this value as this controls the output power off your gateway, the higher this level the higher is the reflected signal (echo) from teleco. I am assuming that the IP Phone side is the one hearing the echo.</FONT></DIV>
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<DIV class=ecsection1 style="MARGIN: auto 0in"><SPAN style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma">Thanks and Best Regards<BR><B><BR>Ahmed A. Elnagar<BR></B>Network Field Engineer</SPAN></DIV>
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<DIV class=ecsection1 style="MARGIN: auto 0in"><SPAN lang=ES style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma; mso-ansi-language: ES">Advanced Computer Technology (ACT)<BR>16 Fawzy Ramah St.Off Shehab St.Mohandessin, Giza, Egypt <BR>Postal Code:12411 Cairo Egypt<BR></SPAN><SPAN style="FONT-SIZE: 6pt; COLOR: #003366; FONT-FAMILY: Tahoma"><BR></SPAN><SPAN class=ecspelle><B><SPAN lang=ES style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma; mso-ansi-language: ES">Mob</SPAN></B></SPAN><B><SPAN style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma">:</SPAN></B><SPAN style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma"> +2010-2833868</SPAN><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma"><BR></SPAN><B><SPAN lang=ES style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma; mso-ansi-language: ES">Website</SPAN></B><B><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Tahoma">: </SPAN></B><SPAN lang=ES style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma; mso-ansi-language: ES">www.act-eg.com<BR><B>E-mail</B></SPAN><B><SPAN style="FONT-SIZE: 10pt; COLOR: #004600; FONT-FAMILY: Tahoma">: </SPAN></B><SPAN lang=ES style="FONT-SIZE: 10pt; COLOR: #003366; FONT-FAMILY: Tahoma; mso-ansi-language: ES"><A href="mailto:aelnagar@act-eg.com">aelnagar@act-eg.com</A></SPAN></DIV></FONT></DIV></DIV>
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<FONT face=Tahoma size=2><B>From:</B> cisco-voip-bounces@puck.nether.net on behalf of Rhodes, Geoff<BR><B>Sent:</B> Wed 09-May-07 10:44 PM<BR><B>To:</B> cisco-voip@puck.nether.net<BR><B>Subject:</B> Re: [cisco-voip] Echo on IP Phones through PRI<BR></FONT><BR></DIV>
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<P><FONT size=2>Please excuse the newbie question, but how do I determine the DSP<BR>version my MGCP gateway is running? It's a CMM blade in our 6509<BR>switch. The IOS on it looks to be 12.4(8a). I'd like to document what<BR>release we are running for future needs.<BR><BR>We get complaints ever once in a while about echo problems. Most of the<BR>time we blow them off unless someone is constantly complaining.<BR><BR>Here are our settings in CCMAdmin for the CMM Gateway:<BR>Echo Cancellation Enable = Enable<BR>Echo Cancel Coverage = 32<BR>Input Gain = 3<BR>Output Attenuation = -3<BR><BR>Thanks for your help.<BR><BR>Geoff Rhodes<BR>Director, Information Technology<BR>Robinson, Bradshaw & Hinson, P.A.<BR>704 / 377-8188<BR>grhodes@rbh.com<BR><BR><BR><BR>-----Original Message-----<BR>From: cisco-voip-bounces@puck.nether.net<BR>[<A href="mailto:cisco-voip-bounces@puck.nether.net">mailto:cisco-voip-bounces@puck.nether.net</A>] On Behalf Of Erick Bergquist<BR>Sent: Wednesday, April 18, 2007 9:12 AM<BR>To: Matthew Melbourne; cisco-voip@puck.nether.net<BR>Subject: Re: [cisco-voip] Echo on IP Phones through PRI<BR><BR>DSP Fimware 4.4.708 has issues which can cause echo, etc. Many people on<BR>the cisco NetPro forums have ran into echo issues with this DSP<BR>firmware. I don't have the exact bug id's handy, but you can try<BR>upgrading to a current 12.4 mainline release if your routers DRAM/flash<BR>can take it. 12.4(13a) has 4.4.23 DSP ware. So far, I have not ran into<BR>any issues yet with DSP firmware 4.4.21 or higher in 12.4 mainline but<BR>YMMV.<BR><BR>If you can't update the IOS, and I don't believe there is a newer 12.3T<BR>release with a newer firmware embedded in it, you can get a standalone<BR>DSP firmware image file to put on the router flash that is a newer<BR>version from TAC.<BR><BR>As far as finding out what gateway a call is using, probably the<BR>quickest way is to go to the phones web page while the call is connected<BR>and look at the stream page for the remote IP address. Other then that,<BR>you would need to check out CDR and/or QRT records if they use QRT<BR>softkey, etc and go into each gateway.<BR><BR>----- Original Message ----<BR>From: Matthew Melbourne <matt@melbourne.org.uk><BR>To: cisco-voip@puck.nether.net<BR>Sent: Wednesday, April 18, 2007 7:50:22 AM<BR>Subject: [cisco-voip] Echo on IP Phones through PRI<BR><BR>We are getting sporadic issues from users on IP phones who are hearing<BR>echo on external calls. From this document is would suggest that echo on<BR>IP Phones is caused by hybrid echo and not any local acoustic echo.<BR><BR><A href="http://www.cisco.com/warp/public/788/voice-qos/echo_ipphone_gateway.html">http://www.cisco.com/warp/public/788/voice-qos/echo_ipphone_gateway.html</A><BR><BR>The MGCP-controlled voice gateways are all running 12.3(14)T7 with DSP<BR>firmware 4.4.708. In CallManager (4.1(3)SR2), echo cancellation is on<BR>for each port, with a "default" echo cancellation coverage of 64ms.<BR>Input gain and output attenuation are set to 0dB.<BR><BR>I have seen suggestions to include the "echo-cancel erl worst-case 3"<BR>command on the voice ports. Can this help in situations of occasional<BR>echo?<BR><BR>Are there any other parameters changes which could help? Could it be a<BR>code/DSP firmware issue? I haven't found a specific echo-related bug<BR>relating to this particular IOS and its embedded DSP firmware.<BR><BR>On occasions, the start of the call is fine but echo comes and goes<BR>during the call.<BR><BR>Is there a quick way of finding out which voice gateway a call is<BR>terminated on (we have 8, and all could be used in a round-robin fashion<BR>for outbound calls).<BR><BR>Cheers,<BR><BR>Matt<BR><BR>--<BR>Matthew Melbourne<BR>_______________________________________________<BR>cisco-voip mailing list<BR>cisco-voip@puck.nether.net<BR><A href="https://puck.nether.net/mailman/listinfo/cisco-voip">https://puck.nether.net/mailman/listinfo/cisco-voip</A><BR><BR><BR><BR><BR>__________________________________________________<BR>Do You Yahoo!?<BR>Tired of spam? Yahoo! Mail has the best spam protection around<BR><A href="http://mail.yahoo.com/">http://mail.yahoo.com</A><BR>_______________________________________________<BR>cisco-voip mailing list<BR>cisco-voip@puck.nether.net<BR><A href="https://puck.nether.net/mailman/listinfo/cisco-voip">https://puck.nether.net/mailman/listinfo/cisco-voip</A><BR><BR>_______________________________________________<BR>cisco-voip mailing list<BR>cisco-voip@puck.nether.net<BR><A href="https://puck.nether.net/mailman/listinfo/cisco-voip">https://puck.nether.net/mailman/listinfo/cisco-voip</A><BR></FONT></P></DIV></BODY></HTML>