[cisco-voip] Listener Echo

[Ed Leatherman]

I'll check those out, thanks Jason

On Fri, Feb 20, 2009 at 7:53 PM, Jason Aarons (US)
<jason.aarons at us.didata.com> wrote:
> Despite whatever you read on CCO about 2-wire to 4-wire, try first
> changing the phone load. You may want to try several loads before
> chasing down a echo canceller, etc.
>
> Older loads (2002-2003) had issues with the mic picking up the speaker
> on 79x0s.
>
> Also use a older 7940/60 measure the ERL and adjust input gain and
> output attenuation as in the bottom of this article (this won't work
> with 7941 or newer phones
>
> http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a
> 0080149a1f.shtml
>
> -----Original Message-----
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Ed Leatherman
> Sent: Friday, February 20, 2009 4:51 PM
> To: cisco voip
> Subject: [cisco-voip] Listener Echo
>
> Anyone had to troubleshoot listener echo?
>
> I've been reading up a good bit on echo from some docs on CCO, but
> it's all related to talker echo. So far what i've googled up gives a
> good definition of listener echo, but nothing really on how to address
> it.
>
> The symptoms some of my call center agents have reported are where
> they are hearing an echo of the caller rather than themselves. The
> echo is very close to the "real" audio from the caller, so i think if
> there was just a little bit less latency out where its getting
> generated, it wouldn't even be perceptible. My call center itself is
> on our campus LAN, network latency between them and the PSTN gateway
> is by and large under ~4ms based on my IPSLA stats.. but I don't think
> this leg of the call has anything to do with the problem.
>
> This doesn't seem like it can be fixed with the echo cancelers on my
> gateways, at least in my limited understanding of how they operate (no
> transmit signal to compare to). This call center deals primarily with
> pharmacies (walgreens, walmart, supermarkets, etc). If I can find some
> sort of pattern here and establish that it's callers from a specific
> phone number or company, is there something on my side I can even do
> to fix this?
>
> I told them to make sure the caller wasn't on a speaker phone and try
> to establish some sort of pattern of problem calls.
>
> --
> Ed Leatherman
> Assistant Director, Voice Services
> West Virginia University
> Telecommunications and Network Operations
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-- 
Ed Leatherman
Assistant Director, Voice Services
West Virginia University
Telecommunications and Network Operations