Dell Latitude D620 ATG - Manual (Page 4)

keyboard status lights
The green lights located above the keyboard indicate the following:
volume control buttons — Press these buttons to adjust the volume.
ambient light sensor — Detects available environmental light and automatically increases or decreases the display backlighting to compensate for low-light
and high-light environments. Press the <Fn> and left-arrow key to enable or disable the sensor (see Using the Ambient Light Sensor ).
mute button — Press this button to turn off the volume.
keyboard illumination lights — Press <Fn> and the right-arrow key to toggle on and off these lights for illumination of the keyboard in low-light environments.
Left Side View
Turns on when the numeric keypad is enabled.
Turns on when the uppercase letter function is enabled.
Turns on when the scroll lock function is enabled.