Dell ST2220 Monitor - Manual (Page 18)

OSD Warning Messages
Personalize There are 2 shortcut keys on the front panel. Select one control menu for each shortcut key to allow direct access.
When the monitor does not support a particular resolution mode you will see the following message :
This means that the monitor cannot synchronize with the signal that it is receiving from the computer. See Monitor Specifications for the
Horizontal and Vertical frequency ranges addressable by this monitor. The recommended mode is 1920x1080.
When monitor enters Power Save mode, the following message appears :
Activate the computer and wake up the monitor to gain access to the
OSD
If you press any button other than the power button the following message will appear: