AOR AR-2300 Operating Manual page 40

You can also force MONO reception by clicking the "Mono" button as follows:
The S-meter can be operated in RMS mode (input signal RMS power displayed) or in Peak mode (input signal peak
power displayed) clicking the "RMS" or "Peak" at the right side of the S-meter.
8-10 Squelch & auto-mute
Squelch and Auto-Mute threshold levels can be controlled clicking the desired value in the S-Meter bar with the left
button of the mouse.
The Auto-Mute function works in the opposite way of the squelch block. It mutes the audio when the RF input level is
GREATER than the desired threshold.
The squelch level is set clicking the S-Meter bar in the S1-S9 zone. A triangle with a left oriented vertical side in the S-
Meter bar indicates the selected squelch threshold.
The Auto-Mute level is set clicking the S-Meter bar in the S9 - S9+70 zone. A triangle with a right oriented vertical side
in the S-Meter bar indicates the selected Auto-Mute threshold.
To disable the squelch and/or the Auto-Mute functions, right click the appropriate S-Meter zone.
The hysteresis of the squelch and Auto-Mute functions is approximately 6 dB.
The selected thresholds are peak values.
Squelch Auto-mute
35