Input/Output Devices

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Various I/O devices have been adopted by mobile handheld devices. The only major output device is the screen, whereas there are several popular input devices, including:

Keyboards: There are two kinds of keyboards: built-in keyboards and external, plug-in keyboards. The problem with the former is that they are too small for touch-typing, whereas the latter suffers from inconvenience.

Fabric keyboards that can be rolled up or folded around the handheld devices are to relieve the problem of external keyboards.

• Touch screens/writing areas with a stylus:

  A touch screen is a display that is sensitive to human touch, allowing a user to interact with the applications by touching pictures or words on the screen, and a stylus is an input device used to write text or draw lines on a surface as input to a handheld device.

  A handheld device equipped with a writing area and a stylus needs a handwriting recognition function, but existing systems do not yet have a satisfactory recognition rate. Graffiti, employed by many handheld devices, is the most popular writing software.

Some mobile handheld devices can also react to voice input by using voice recognition technology.