System Functions; Display Functions; Speaker Functions - Dell Latitude C640 User Manual

System Functions

Display Functions

Switches the video image to the next display in the following sequence: the integrated display,
an external monitor, and both displays simultaneously
Increases brightness on the integrated display only (not on an external monitor)
Decreases brightness on the integrated display only (not on an external monitor)
Power Management
Activates the power management mode of your choice. You can program this keyboard shortcut
on the Advanced tab in the

Speaker Functions

If no sound comes from the speakers, press
Opens the Windows Security window
Enables and disables the numeric keypad
Enables and disables scroll lock
Power Options Properties window.
and adjust the volume.