[cisco-voip] 9971 echo on speakerphone

[Eric Pedersen]

They're running firmware 9.2(1) so it's fairly recent. Are there any configuration or diagnostic features for the DSPs? I couldn't find any.


From: Wes Sisk [mailto:wsisk at cisco.com]
Sent: 26 October 2011 9:49 AM
To: Eric Pedersen
Cc: cisco voip
Subject: Re: [cisco-voip] 9971 echo on speakerphone

What phone load are you using? I'm not aware of anything along these lines being tracked on the 99xx phones in recent loads.

Stepping back to the fundamentals of echo - If the mic is too sensitive and then environment introduces noise then echo is unavoidable.  DSPs train on the audio signal that is sent out to the speakerphone speaker.  If that audio is mixed with noise in the environment then the audio signal that comes back into the speakerphone microphone will be distorted.  Because of the distortion from the noise the ECAN will not recognize the echo signal in the incoming audio.  This could just come down to microphone sensitivity. I believe there were issues with mic sensitivity in early phone loads.

/wes


On Oct 26, 2011, at 11:31 AM, Eric Pedersen wrote:


We are having intermittent problems with echo on calls to 9971 phones on speaker.  I've been able to reproduce this, but not consistently and it seems to only occur on some calls, primarily internal though I suppose PSTN calls may be having the same problem but the gateway DSPs are suppressing it.  Basically when someone calls me on my 9971 and I take the call on speakerphone they hear their own voice echoing and background HVAC noise.  It seems like the built-in echo canceller is not working when this happens.  I've tried different phones in the same physical space with the problem occurring on some but not others so I don't think it's the room layout.  Has anyone else seen anything like this?

Thanks,
Eric


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