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<DIV dir=ltr align=left><SPAN class=096351514-02092010><FONT face=Arial
color=#0000ff size=2>Cool. Didn't know that. Thanks
all!</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=096351514-02092010><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=096351514-02092010><FONT face=Arial
color=#0000ff size=2>jeff</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=096351514-02092010><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=096351514-02092010><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> Lelio Fulgenzi [mailto:lelio@uoguelph.ca]
<BR><B>Sent:</B> Wednesday, September 01, 2010 4:24 PM<BR><B>To:</B> Wes
Sisk<BR><B>Cc:</B> Jeff Ruttman; Cisco VOIP<BR><B>Subject:</B> Re: [cisco-voip]
Echo Cancellation and 7911 Phone Loads<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>…and you can remove the "customer" part completely to get the public
version of the link (if available) to give to people without a CCO
account. <BR><BR>…
<DIV>Don't look at me, my iPod maid that spilling mistake.<SPAN
class=Apple-style-span
style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.296875); -webkit-composition-fill-color: rgba(175, 192, 227, 0.230469); -webkit-composition-frame-color: rgba(77, 128, 180, 0.230469)"> </SPAN></DIV></DIV>
<DIV><BR>On 2010-09-01, at 4:45 PM, Wes Sisk <<A
href="mailto:wsisk@cisco.com">wsisk@cisco.com</A>> wrote:<BR><BR></DIV>
<DIV></DIV>
<BLOCKQUOTE type="cite">
<DIV>Hi Jeff,<BR><BR>Apologies for the 'partner' links. Most of the time you
can replace 'partner' with 'customer' and get the
content.<BR><BR>/Wes<BR><BR>Jeff Ruttman wrote:
<BLOCKQUOTE
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<DIV dir=ltr align=left><SPAN class=300011515-01092010><FONT face=Arial
color=#0000ff size=2>Thanks again, Wes.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=300011515-01092010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=300011515-01092010><FONT face=Arial
color=#0000ff size=2>I see you mentioned SLIPS, and I had seen that as a
possible cause, but there are zero, so I had ruled that out. Should
have had that in my little list, though.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=300011515-01092010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=300011515-01092010><FONT face=Arial
color=#0000ff size=2>I've certainly got more to go on now, and I can
see this last doc you referenced. (I'm not a Partner, so I was
"forbidden" some of the other docs you linked me to.) Crappy part is
the echo is intermittent--of course--so all I can really do is make a change
then wait and see. I've sent a number of calls out that circuit to
test myself, and I've not heard any echo.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=300011515-01092010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=300011515-01092010><FONT face=Arial
color=#0000ff size=2>jeff</FONT></SPAN></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> Wes Sisk [<A
class=moz-txt-link-freetext href="mailto:wsisk@cisco.com"><A
href="mailto:wsisk@cisco.com">mailto:wsisk@cisco.com</A></A>]
<BR><B>Sent:</B> Wednesday, September 01, 2010 9:54 AM<BR><B>To:</B> Jeff
Ruttman<BR><B>Cc:</B> Cisco VOIP<BR><B>Subject:</B> Re: [cisco-voip] Echo
Cancellation and 7911 Phone Loads<BR></FONT><BR></DIV>Hi
Jeff,<BR><BR>Inline, ws.<BR><BR>Jeff Ruttman wrote:
<BLOCKQUOTE
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0px! important; BORDER-TOP: medium none; PADDING-LEFT: 0px! important; MARGIN-LEFT: 0px! important; BORDER-LEFT: medium none; MARGIN-RIGHT: 0px! important; BORDER-BOTTOM: medium none"
cite=mid:07365C3161D8D8419EE51C3834C0220502D8F658@ma1-exc01.ec2802.elderc.org
type="cite">
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>Thanks Wes. </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>Well I've expanded echo cancellation on
the gateway. (PRI with MGCP, CCM6.1) So your first
paragraph is saying that most likely echo is generated too "far away" (too
much delay) from my GW to cancel the tail end echo coming into our
system--even with my expanded echo cancellation in place. So only
the telco might have a chance of cancelling that echo "closer to" the echo
source.</FONT></SPAN></DIV></BLOCKQUOTE>ws: echo is generated too far from
the ipphone, like at the the other endpoint. If you call me and hear your
own voice then most likely the echo is being generated in my phone.
Your gateway is closest to me so will have the best chance of canceling the
echo as the original signal and echo signal are closest in time in your
network at the gateway. But, in the end, it really is a problem with
my customer premise equipment (CPE). I should be canceling the echo.
The best place to fix it is in my network. Next best is in the
carrier, next is in your CPE.<BR>
<BLOCKQUOTE
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<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>As I understand it, I might also change phone loads
(hence my question about 7911s). And I might try some
gain/attenuation settings on the GW as well--or so I've
read.</FONT></SPAN></DIV></BLOCKQUOTE>ws: Yes, there is tuning on the
gateway to get the most out of the available ecans. If the echo is coming
back within the cancellation coverage then you just need to get levels and
ERL in line so the ecans can do their jobs.<BR>
<BLOCKQUOTE
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0px! important; BORDER-TOP: medium none; PADDING-LEFT: 0px! important; MARGIN-LEFT: 0px! important; BORDER-LEFT: medium none; MARGIN-RIGHT: 0px! important; BORDER-BOTTOM: medium none"
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<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>So in a VOIP system that has echo, I
can:</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>1. Bug the telco</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>2. Expand echo cancellation on the
GW</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>3. Attenuation/gain statements on
GW</FONT></SPAN></DIV></BLOCKQUOTE>There are several parameters on gateways
for possible tuning. These include:<BR>ecan coverage<BR>NLP - non linear
processor<BR>ERL - echo return loss - primarily affected by Input Gain and
Output Attenuation<BR>Noise - any noise introduced on the circuit causes the
echo signal to not match the original signal. This prevents echo from being
detected and canceled. Examples of noise include any slips or errors
on T1's and electrical cables (60Hz, fluorescent lights especially) located
too close to analog (FXS/FXO) connections. I believe the parameters
are covered pretty well here:<BR><A class=moz-txt-link-freetext
href="http://www.cisco.com/en/US/customer/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml"
moz-do-not-send="true"><A
href="http://www.cisco.com/en/US/customer/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml">http://www.cisco.com/en/US/customer/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml</A></A><BR>
<BLOCKQUOTE
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cite=mid:07365C3161D8D8419EE51C3834C0220502D8F658@ma1-exc01.ec2802.elderc.org
type="cite">
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>4. Change phone load</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>At least so far that's all I've found I can tinker
with. Is that about it?</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>Anyone use attenuation or gain statements on their
GWs? I know the statements, but I don't know what their function
really is, whether I would use one or the other or both, or what I would
set them to.</FONT></SPAN></DIV></BLOCKQUOTE>ws: see the article
above. Use IG and OA to get ERL that works for ECAN.<BR>
<BLOCKQUOTE
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<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>Thanks</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010><FONT face=Arial
color=#0000ff size=2>jeff</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=263310719-31082010></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN
class=263310719-31082010></SPAN> </DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> Wes Sisk [<A
class=moz-txt-link-freetext href="mailto:wsisk@cisco.com"
moz-do-not-send="true"><A
href="mailto:wsisk@cisco.com">mailto:wsisk@cisco.com</A></A>]
<BR><B>Sent:</B> Tuesday, August 31, 2010 2:00 PM<BR><B>To:</B> Jeff
Ruttman<BR><B>Cc:</B> Cisco VOIP<BR><B>Subject:</B> Re: [cisco-voip] Echo
Cancellation and 7911 Phone Loads<BR></FONT><BR></DIV>Talker echo is
usually caused by echo at far end tail circuit. With VOIP that delay
is going to be too long for the talker's phone to cancel. It will
have to canceled closer to the source of the echo.<BR><BR>Otherwise,
AFAIK, all cisco phones (except soft) have local ecan to prevent speaker
audio from going back into mic.<BR><BR><BR><A class=moz-txt-link-freetext
href="http://www.voiptroubleshooter.com/problems/echo.html"
moz-do-not-send="true"><A
href="http://www.voiptroubleshooter.com/problems/echo.html">http://www.voiptroubleshooter.com/problems/echo.html</A></A><BR><A
class=moz-txt-link-freetext
href="http://www.cisco.com/en/US/partner/docs/ios/solutions_docs/voip_solutions/EA_ISD.html"
moz-do-not-send="true"><A
href="http://www.cisco.com/en/US/partner/docs/ios/solutions_docs/voip_solutions/EA_ISD.html">http://www.cisco.com/en/US/partner/docs/ios/solutions_docs/voip_solutions/EA_ISD.html</A></A><BR><A
class=moz-txt-link-freetext
href="http://www.cisco.com/en/US/partner/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml"
moz-do-not-send="true"><A
href="http://www.cisco.com/en/US/partner/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml">http://www.cisco.com/en/US/partner/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml</A></A><BR><BR>/Wes<BR><BR>Jeff
Ruttman wrote:
<BLOCKQUOTE
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cite=mid:07365C3161D8D8419EE51C3834C0220502D8F657@ma1-exc01.ec2802.elderc.org
type="cite">
<DIV><SPAN class=997510914-31082010><FONT face=Arial
size=2>Greetings,</FONT></SPAN></DIV>
<DIV><SPAN class=997510914-31082010></SPAN> </DIV>
<DIV><SPAN class=997510914-31082010><FONT face=Arial size=2>Can someone
confirm or deny my memory? I recall reading that phone loads for
7911 phones don't really contain echo cancellation programming. In
looking now, I can't find much info on echo cancellation in relation to
different phone models/loads in general and nothing on
7911s.</FONT></SPAN></DIV>
<DIV><SPAN class=997510914-31082010></SPAN> </DIV>
<DIV><SPAN class=997510914-31082010><FONT face=Arial size=2>We have an
office mostly full of 7911s recently complaining of talker echo.
There are loads out on <A
href="http://cisco.com">cisco.com</A> newer than the ones we're
using, and while it's not hard to change phone loads, it would be
pointless to do it if the phone loads don't contain echo
cancellation.</FONT></SPAN></DIV>
<DIV><SPAN class=997510914-31082010></SPAN> </DIV>
<DIV><SPAN class=997510914-31082010><FONT face=Arial size=2>Any
insight?</FONT></SPAN></DIV>
<DIV><SPAN class=997510914-31082010></SPAN> </DIV>
<DIV><SPAN class=997510914-31082010><FONT face=Arial
size=2>Thanks</FONT></SPAN></DIV>
<DIV><SPAN class=997510914-31082010><FONT face=Arial
size=2>jeff</FONT></SPAN></DIV><PRE wrap=""><HR width="90%" SIZE=4>
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