AT&T 5870 - Manual (Page 23)

20
Ringer Volume
1 Make sure the base is not in use.
2 Pressing and holding , then press VOL
+ or VOL - to adjust the ringer volume. Each
time you press + or - you will hear how loud
the setting is.To turn the ringer off, press -
until you hear no tone.
M M M
O O O
FEATURE SETUP – BASE