Aastra 610d User Manual page 33

Basic functions
Switching ringer off at call
Illumination / display dimming
Keyboard/Display/Display dimming
Activating the display illumination
Changing the brightness/contrast of the display
Aastra 610d
Settings Display
Aastra 612d /620d/622d/630d/632d/650c
UUU Settings Display
Muting the handset
You are making a call.
UUU
Contrast
Brightness
Settings Illumination
C
UUU