Casio GB-6900B User's Manual For Watch Functions page 52

●
2
●
3
Mute indicator
●
. P ress.C.nine.times.to.display.the.button.operation.
tone.setting.screen.
See "Configuring Current Time and Date Settings
Manually" (page E-19).
The screen will show either [KEY ] or [MUTE].
●
. P ress.D.to.toggle.the.setting.between.[KEY ].(ON).
and.[MUTE].(OFF).
When [MUTE] (OFF) is selected, a Mute indicator is
displayed to indicate that the button operation tone
will not sound.
E-51