Planar PX23MW - Manual (Page 19)

Warning Signal
This message means that the LCD Display has been powered on but it
cannot receive any signal from the computer graphics card. Check all the
power switches, power cables, and VGA signal cable.
4 Out Of Range
This message means that the signal of the computer graphics card is not
compatible with the LCD Display. When the signal is not included in the
compatibility mode we have listed in the Appendices of this manual, the
LCD Display will show this message.
Sometimes you may see warning messages for this LCD Display.
This means that the LCD Display cannot correctly receive the signal
from the computer graphics card.
4
Signal
15
No Input Signal