The firstVague: date=March 2009 PDA is considered to be the CASIO PF-3000 released in May 1983. GO Corp. was also pioneering in the field. The term was first used on January 7, 1992 by Apple Computer CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevada, referring to the Apple Newton. In 1996 Nokia introduced the first mobile phone with full PDA functionality, the 9000 Communicator, which has since grown to become the world's best-selling PDA and which spawned a category of phones called the smartphone. Today the vast majority of all PDAs are smartphones, selling over 150 million units while non-phone ("stand-alone") PDAs sell only about 3 million units per year. The RIM Blackberry, the Apple iPhone and the Nokia N-Series are typical smartphones.

Typical features

Currently, a typical PDA has a touch screen for entering data, a memory card slot for data storage and at least one of the following for connectivity: IrDA, Bluetooth and/or WiFi. However, many PDAs (typically those used primarily as telephones) may not have a touch screen, using softkeys, a directional pad and either the numeric keypad or a thumb keyboard for input.

Software typically required to be a PDA includes an appointment calendar, a to-do list, an address book for contacts and some sort of note program. Connected PDAs also typically include E-mail and Web support.

Touch screen

Many original PDAs, such as the Apple Newton and Palm Pilot, featured touch screens for user interaction, having only a few buttons usually reserved for shortcuts to often used programs. Touch screen PDAs, including Windows Pocket PC devices, usually have a detachable stylus that can be used on the touch screen. Interaction is then done by tapping the screen to activate buttons or menu choices, and dragging the stylus to, for example, highlight. Text input is usually done in one of four ways:

• Using a virtual keyboard, where a keyboard is shown on the touch screen. Input is done by tapping letters on the screen.
• Using external keyboard or corded keyboard connected by USB, IR or Bluetooth.
• Using letter or word recognition, where letters or words are written on the touch screen, and then "translated" to letters in the currently activated text field. Despite rigorous research and development projects, end-users experience mixed results with this input method, with some finding it frustrating and inaccurate, while others are satisfied with the quality. Recognition and computation of handwritten horizontal and vertical formulas such as "1 + 2 =" was also under development.
• Stroke recognition (one Palm implementation is called Graffiti). In this system a predefined set of strokes represents the various characters used in input. The user learns to draw these strokes on the screen or in an input area. The strokes are often simplified character shapes to make them easier for the device to recognize.