Dell U2711 Monitor - Manual (Page 19)

If either VGA or DVI-D input is selected and both VGA and DVI-D cables are not connected, a floating dialog box as shown below appears.
If either Composite, or Component input is selected and the cables are not connected or the video source is turned off, the screen does
not have an image. If any button is touched (except power button), the monitor displays the following message:
or
or
4
OSD Menu
Use this key to open the on-screen display (OSD). See Using the OSD Menu .
5
Exit
Use this key to exit the OSD menu.
6
Power button
(with power light
indicator)
Use the power button to turn the monitor on and off.
The blue light indicates the monitor is on and fully functional. An amber light indicates power save mode.