8.1.1 It should be possible to adjust the contrast
and brightness of the display provided, as applicable to the display
technology. It should be possible to dim the display. The range of
control should permit the display to be legible under all ambient
light conditions.
8.1.2 It should be possible for the navigator
to reset the values of contrast and/or brightness to a preset or default
condition.
8.1.3 Where magnetic fields degrade the presentation
of navigation information, a means to neutralise the effect of magnetic
fields should be provided.