Level central point can be adjusted using the knob below. Press the knob
twice until three beeps are played, it means central point adjustment is ready.
If no adjustment has been made within 5 seconds, the knob function returns
to volume setting automatically.
3.2.7 Squelcher and Denoiser
KC908 comes with a squelching function, which is designed to turn off
sound ouput when no signal is present or the present signal is not desired, to
avoid making unnecessary noise.
Squelchers are: level squelcher, conversational voice squelcher, CTS, DCS.
Level squelcher: When the level of the signal is lower than the threshold,
sounds are muted.