Root Causes of Echo in calls

[eija.hallor]

Hi all,

We have narrowed down some of the symptoms of sound trouble in WebEx meetings and our most common issue is echo on the line.

Many users join meetings both with their PC and with a mobile phone, where PC acts as the screen to view presentation and the phone is used for the audio connection. We are recommending users to always connect the phone with their Attendee ID, as we have thought at least that the PC sound else may cause acoustic echo in the phone which is likely very close to the PC (muted but still having an active mic). We have seen instances where connecting the PC login and the call in user solves the problem but we want to understand the technical part of what is happening.  

Anyone got a good explanation on why phones may cause an acoustic echo even if PC is muted?

Thanks!

[Manish Gogna]

While it may be difficult to pinpoint a cause of echo without proper probing and troubleshooting, the various factors resulting in echo and their fixes on VoIP networks are discussed in detail in the following doc

http://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/voip_solutions/EA_ISD.html?referring_site=RE&pos=1&page=http://www.cisco.com/c/en/us/support/docs/voice/voice-quality/19640-echo-ipphone-gateway.html#wp1041351

Manish