Siemens SIMATIC Box PC 840 Manual page 45

Please read the following note referring to the operation of a flat display and an
external monitor:
Notice
The default setting of the display provides the simultaneous operation of a flat display
and an external monitor. If no front display element is connected, the display is
effected on the external monitor with a resolution of 800 x 600 pixels. Modes with a
lower resolution and text modes are expanded to this format.
To optimize the screen display for an external monitor, select "Hardware Options"
under Setup in the main menu and set "CRT/LCD selection: CRT enabled". A
resolution of 1024 x 768 pixels with a higher refresh rate is then possible.
Using a Mouse
You can connect both a PS/2-USB and a serial mouse to the
SIMATIC Box PC 840.
SIMATIC Box PC 840 Manual
A5E00085984-04
Setting Up and Operating the SIMATIC Box PC 840
3-13