Sony spp-n1025 - Manual (Page 32)

32 US Telephone Features
To turn the ringer on again
Follow the instructions described in “Setting the ringer type” above.
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