Spectec SDV-841/842 - Manual (Page 20)

Assigning Hot Keys
NVD provides several small programs that make NVD functionality more
accessible. These programs can be assigned to hot keys for even greater
control.
On Pocket PC devices these program shortcuts are located in:
\Windows\Start Menu\Programs\Virtual Display
On Handheld PC devices these program shortcuts are located in:
\Windows\Programs\Virtual Display
These shortcuts can be assigned to hardware buttons using your devices
Buttons Control Panel applet. Please consult your device's user manual for
instructions on assigning hardware buttons.