Personal digital assistants (PDAs) are small, hand-held computers. They use a form of touch screen technology, using a light pen or stylus as an input device rather than a keyboard. In addition, a detachable keyboard or a voice recorder can be used. PDAs are versatile information processing appliances. They are used frequently as personal information managers (PIMs) to record telephone numbers, addresses, appointments, and to-do lists. Also, PDAs can synchronize with microcomputers to transfer e-mail, text documents, spreadsheets, files, or databases. Other types of PDAs incorporate an integrated modem to connect with the Internet or to dial-up another computer in order to transfer data.

Some PDAs use wireless communications technology, providing great mobility. This use of wireless technology allows companies to provide PDAs to their employees in situations where laptops would be unworkable.

Palmtops, which are small computers that fit in the palm of...