Sharp PC-9800T Manual page 45

Increases the LCD screen brightness.
Decreases the LCD screen contrast (only for DSTN models).
2
Increases the LCD screen contrast (only for DSTN models).
Turns on and off the battery low warning beep.
Turns on and off the screen backlighting.
Puts the notebook in suspend mode (to RAM or to Disk,
according to the setup selection).
2-6 Basic Operations