Sharp UX-310 Operation Manual page 32

Volume Adjustment
Ringer
1
Press the UP or DOWN key. (Make
sure the SPEAKER key has not been
pressed and the handset is not lifted.)
The ringer will ring once at the
selected level, then the date and
time will reappear in the display.
2
If you selected RINGER:OFF OK ?,
press the START key.
30
UP
DOWN
or
Display:
RINGER: HIGH
RINGER: MIDDLE
RINGER: LOW
RINGER:OFF OK ?
START