HP Jornada 420 - Manual (Page 36)

32 Hewlett-Packard Jornada 420 Palm-size PC
HP settings allows you to adjust brightness, contrast, and
volume by using the Action button. Hold the Start button to
open HP settings, and use the Action button to cycle the
profiles and to select the preferred one.
Settings tab
The HP Jornada has four preset HP settings profiles. You can
launch any profile by selecting the radio button associated with
it. You can also adjust any of the settings in any profile to suit
your preference.