Jeppesen FliteDeck 3 - Manual (Page 268)

Troubleshooting and Getting Help
271
A touchscreen is an input device that allows you to operate a PC by simply touching
the display screen. A disadvantage to touchscreens is that you can not brace your
hand on the screen. Laying the screen in your lap often causes problems because
maps and other equipment may accidentally be positioned on the display. This may
generate random actions that were not intended. Turbulence also causes the same
problems as those found when using a touch pad.
Plastic pens or finger pointers can make the display easier to use and more precise.
This negates some of the touch screen advantage over the active or passive pens
because you now have a pen to keep track of, but if you drop it, you can just go
back to your finger.
Most touchscreens are easy to scratch and you should NEVER use a metal tipped
object to point with because the scratches will eventually make the screen impossible
to see through.
Trackballs
A trackball is a pointing device consisting of a ball housed in a socket containing
sensors to detect rotation of the ball about two axes-like an upside-down mouse, but
with the ball sticking out more. You roll the ball with your thumb, fingers, or the
palm of your hand to move a cursor. Trackballs are unfamiliar to most people.
Because your hand is braced, trackballs can work very well in turbulence once a
comfortable trackball is found.
There are many different forms of trackballs. Some run with the index finger or index
and middle finger tips. Others trackballs can be run with the palm or with the thumb.
A thumb trackball with switches under the fingers requires NO arm movement while
the others can require varying amounts of arm movement. Also the thumb type
provides the best hand bracing in turbulence.
Presentation Pointers
Presentation pointers are typically hand-held wireless devices that look like TV
remote controls. The simple ones are NOT a replacement for a mouse, but the high-
end devices can perform full mouse support. Some use a rocker pad that lets you
drive the pointer around the screen. Some are gyro based and respond to being
tilted. Both types can work well in turbulence because they allow a good grip and are
independent of the motions induced by the turbulence.
Input Device Troubleshooting
When using my pen to select or tap an item, something other than what was
intended is selected.
To improve the accuracy of the pen position, you should calibrate your Tablet PC
digitizer. The digitizer is basically a thin film built into the screen that interacts with
the magnetic tip in your pen. The calibration is also affected by how you view the
screen (from above, on the right or left, or straight on). If you complete a calibration
viewing the screen on the left, you will view the calibration marks at a different angle
then if you looked at it straight on. To calibrate the digitizer: