Most Softphone echo problems occur due to acoustic echo, the sound from the earpiece or speaker going back into the microphone on the end-user device.
This is a known issue with audio feedback. Lower the volume setting for either the microphone or the speakers using the slider controls on the front of the Softphone. If the speaker or microphone volume is too high, then the earpiece or speaker output is picked up by the microphone and is heard by the calling party.
To resolve this issue, perform these steps:
Go to the window's volume control. Double-click on the speaker icon in the system tray.
Select Options > Properties
Under Show the volume controls, make sure Microphone is selected.
Press OK to go back to the Playback volume controls window.
Make sure that the Microphone is set to MUTED. This disables feedback from the microphone to the speaker and vice versa. There is another entry for microphone under the Recording volume controls. It should not be muted since it is used to record your voice.
For additional resolutions to this problem, refer to these options:
Make sure your microphone jack is plugged into the correct socket. If you have a USB headset, make sure that you have chosen the USB device as your primary device for recording or playing back audio.
Run the sound recorder program, mute the microphone, and speak loudly to see if it is recording something. If it records, there is something wrong with the connections.
Play back a wave file using media player while you try to record using sound recorder (with the microphone muted). You still should not record anything. If you do, then there is a problem.
If none of these procedures resolves the problem, change the HKEY_CURRENT_USER/Software/Ciscosystems/CCNMediaterm/1.0 registry key. Change the JitterBufferTime default from the 180s to 30s.