Echo Issues (Echo Cancellation); Using Internal Speakers On A Modern Tv; Pop Noise After Unexpected Restart; Custom Audio Tc Console (C40, C60, C90) - Cisco TelePresence C20 Troubleshooting Manual

Echo issues (echo cancellation)

The cause of echo problems can be:
• Using internal speakers on a modern consumer TV. See below for explanation and techniques
to fix this.
• Echo issues may occur immediately after restarting the system.
• Movement of the microphones or speakers during a call.
• Double-talk – both parties in the call speaking simultaneously.
• Very high noise levels
• Having the microphone too close to the speakers. Try moving the microphone further away.
• Having echo cancellation disabled.
You can see more information regarding room setup recommendations in the
Room Primer guide:
http://www.cisco.com/en/US/docs/telepresence/endpoint/misc/user_guide/
video_conferencing_room_primer_ver02.pdf.
NOTE The most likely cause for an echo heard locally is a problem with the far-end system.
General checks
Check that the input for each microphone you have connected to the system has echo control turned
on. This is the default setting. if it is turned off the far-end will hear themselves. Echo control should
only be turned off when using an external echo cancellation.
D15029.01 Troubleshooting Guide TC6.0, April 2013.

Using internal speakers on a modern TV

if you are using the internal speakers on a modern TV the various picture enhancing modes on the
TV delay the audio whilst the image is being processed. This can result in the audio being outside the
acceptable window for echo cancellation thus causing the far end to hear an echo.
There are various workarounds to try if you are experiencing this problem:
• Try and experiment on the TV with various picture modes looking for the one that processes
the image the least. This can be called for example Game mode on some TVs.
• rather than trying to use the internal speakers on the TV, use an external amplifier and speak-
ers or powered speakers and see if this resolves the problem.
• You can experiment with the experimental setting ECReferenceDelay and try changing this
from 0 to a higher value. The setting is located under
-> Experimental -> Audio
Video Conferencing
Figure 15 - EcReferenceDelay Value

Pop noise after unexpected restart

if the system restarts unexpectedly, and occasionally even during a controlled restart, you might hear a
popping noise from the systems audio speakers. This is a normal operation and is not considered a fault.

Custom Audio TC Console (C40, C60, C90)

You can use the TC Console to configure advanced audio settings on the C40, C60 and C90 codecs.
For more detail on TC Console please see the developer forum at
telepresence-developer/tools/integrators/tc-console. Documentation can be found within the application.
You should be aware that once these settings are synced to the codec a script is executed at startup
and these settings are persistent.
You can also use this application to check the microphones. For more information on this see
"Microphones" on page 18.
15
Troubleshooting Guide TC6.0
Configuration -> System Configuration
and look under ExRefernceDelay.
http://developer.cisco.com/web/
Copyright © 2013 Cisco Systems, Inc. All rights reserved.