11-23-2009 01:18 PM - edited 03-21-2019 01:49 AM
We replaced our UC520 with a new UC540. We are experiencing echo when we are on external calls. It does not matter what line we are on or what phone we are using. The echo is only heard on our side. It is not heard on the phone on the other end. It happens on all external calls. The echo is a static sounding echo.
The problem did not occur on the UC520.
Any one have any ideas?
11-23-2009 01:59 PM
I know that the 8.0.0 software pack has been released for the UC540. Is the UC540 running the 7.1.3 release, or is it running the 8.0.0 release? The upgrade to the 8.0.0 release might fix your echo problem.
03-17-2010 09:08 AM
I have been experiencing this with several uc540 and uc560's that are running 8.0. I tested this on my lab uc520 running 7.1.3 and could not hear an echo. as soon as I upgraded to 8.0 I could hear an echo on incoming PSTN calls only. The echo was in the initial 1 or 2 seconds of the call, then it would go away. So far only UC's using FXO ports for PSTN connection are hearing it from what I can tell and it does not happen on every call and it doesn't matter what line its coming in on. I have a tac case open so we will see what comes out of it.
04-22-2010 05:38 AM
Any update on this case I have a 540 with the same issue, but it's running version 7 still..
Thanks
04-22-2010 07:08 AM
Bob,
Try playing with the input gain and output attenuation of your FXO ports in order to adjust this.
Marcos
04-23-2010 07:48 AM
How's that done Marcos?
Searching under Bug Toolkit I found a case simular, and it says the issue is the DSP (single) How many DSP's are in the 540 ans are they assigned dedicated to the FXO ports? If so I'm thinking of moving ports to see if the problem is tied to one DSP.
What was the Bug ID for the case opened?
04-26-2010 02:54 PM
Bump
05-04-2010 09:03 AM
Hi Bob,
Here is a document that explains the root cause of some echo problems:
http://www.cisco.com/en/US/partner/tech/tk652/tk698/technologies_tech_note09186a0080149a1f.shtml
You can play around with different gain values. This is done under the "voice-port 0/1/X" CLI for FXO. The commands are "input gain" and "output attenuation". A negative dB value for gain means the signal strength is being diminished, while a negative value in attenuation means it is being amplified. The total signal power is doubled every 3 dB.
Marcos
05-04-2010 06:41 PM
Thanks Marcos,
It does seem to be on the handset only.
I will review the commands. I assume CCA will not choke on them once input?
Bob
05-04-2010 09:11 PM
What model are the phones?
05-05-2010 05:28 AM
504G's,
I tried almost every other phone (not on this UC) and never had this issue.
Bob
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