Personal digital assistant (PDA) has become the most popular apparatus with the majority of consumers because of its small size, multi-function data processing, large storing capacity, etc. Personal digital assistants are compact computers designed to be carried easily in a purse, brief case or pocket. In recent years, they have become an essential item for both business and non-business users. This is because the PDA is light-weight, easy to start, highly expandable and has a complete range of accessories allowing the users to install various kinds of application software to meet their needs. By virtue of their size, palmtop computer systems are also lightweight and so are exceptionally portable and convenient. PDAs are readily carried about in a briefcase or purse, and some palmtops are compact enough to fit into a person's pocket. Owing to their compact size, personal digital assistants are easily carried and transported by their users, allowing information to be entered and retrieved from a large number of settings and environments not normally accessible by traditional desktop computing units. Nowadays people are in pursuit of high efficiency, causing them to change from conventional diaries, personal computers and notebook computers to more portable computer devices. Personal digital assistants are popular both as portable computers and as wireless communication devices. With a typical PDA, users can arrange schedules, search for contact information, browse outstanding appointments, take immediate memos, receive and send emails, play games and perform other tasks.

Personal digital assistants are adapted to perform a variety of functions including organizing, computing, paging, internet browsing, cellular communication and even global positioning. Personal digital assistants are utilized in a variety of applications. Personal digital assistants provide a user with the convenience to be able to store diaries, meeting schedules, and address books in a compact, transportable form as well as to be able to instantly add new entries such as meeting notes, new addresses etc. A PDA provides computing and information storage and retrieval capabilities for personal or business use. In general, the personal digital assistant is a multi-media product having several functions such as a cellular phone, wireless facsimile, a radio pager, and an electronic pocketbook. Personal digital assistants can store a substantial amount of data such as schedule data, address book data, to-do list data, and a note pad data. It can store thousands of pieces of personal information including address lists, schedules, agenda, and memos. Data communication, including Internet connection, PSTN connection to an information media like UNITEL, and fax communication, has recently become the most significant function of the PDA. In addition, many PDAs are capable of running a variety of application software packages. A PDA can transfer its stored information to a host computer and receive information from the host computer by using a portable information terminal. Many existing PDAs offer the ability to wirelessly transmit and receive electronic-mail (e-mail) messages, browse shares-related information, record revenue and expenditure, browse e-books, games, spreadsheets, databases, information about daily life and wireless communication, etc.

A personal digital assistant may include a fold down display screen and a control panel. The PDA enables a user to easily access a small and portable terminal using a pen or voice, instead of a conventional keyboard, and provides a graphic user interface (GUI) environment. The display screen may be a touch screen type or a or pressure sensitive screen that reacts to touches made by a user controlling a pixel pen or a stylus. Such a display or screen offers a graphical user interface that allows the user to invoke and direct the information processing capabilities of the PDA and to input information by a simulated keypad. With appropriate software, the stylus may also be used to draw lines and to write symbols, such as cursive alphanumeric characters, by moving its tip over the screen.

Personal digital assistants have evolved to become effective tools to manage personal daily transactions due to the conveniences in carrying and data access via the Internet. Some personal digital assistants also incorporate a wireless communication link, allowing the unit to operate as a portable facsimile device, Internet access device and/or pager. A personal digital assistant may be coupled to the Internet via a mobile phone connected to a wireless communications network to conduct information transmission. Information can also be downloaded into a PDA by way of a connection or coupling link between the PDA and a personal computer. PDAs also include external connector used during synchronization procedure with an external database located in a local or remote PC. PDAs always have several connecting ports for electrically connecting to other peripheral devices. he PDA also can electrically connect to other peripheral devices through the add-on card. Some PDAs have built-in wireless communication modules. In addition to being used as beepers, they can also receive real-time information such as stock market news, traffic statuses, weather predictions, and real-time news. The process of loading data into a personal digital assistant or reading information from a PDA is frequently referred to as hot linking.