I hear an echo during the call. What should I do?
Perform a manual room calibration (trimming). This is heard as static of about 0.5 seconds in length. From the remote or the keyboard, do the following:
* Konftel 50 and 60W: Press the Trim button.
* Konftel 100/D and 100/R: Press the + and - volume buttons simultaneously.
* Konftel 100, 200 and 200NI: Press the volume buttons (down arrow /up arrow) simultaneously or press the trim button on the remote.

You could also try to lowering the volume on the Konftel to improve the audio quality.