Sony SPP-933 - Manual (Page 24)

24 US Telephone Features
Checking the ringer type
1
Press (PGM).
2
Press (#) or (*TONE).
3
Press (0).
The currently selected ringer sounds.
4
Press (OFF).
Note
If you hear no sound (only key beep), the ringer on the handset has been turned
off.
Adjusting the ringer volume level of the
base phone
Set the RINGER switch on the base phone to HIGH or LOW. To turn
the ringer off, set it to OFF.
Setting the ringer type (continued)
RINGER switch