Keyboard

After punch cards and paper tape, interaction via teletype-style keyboards became the main input device for computers. During the 1980s and 1990s almost all computers came equipped with them as the main form of interaction, and most users are familiar with using them.

There are different types of keyboard technologies.

The most popular layout of keys on the modern-day English keyboard is called the QWERTY design, based on the most popular typewriter keyboard layout further extended to the standard 104-key PC keyboard layout, with the addition of cursor keys, a calculator-style numeric keypad, two groups of special function keys, a key for the Windows Start menu (on IBM and clones), and other modifier keys. Some computer manufacturers have added keys specifically related to the Internet and e-mail, but these have not become standard.

The fastest typists (as of 2007) use a stenograph, a kind of chorded keyboard used by most court reporters and closed caption reporters.

Despite the development of alternative input devices such as the mouse, touch sensitive screens, pen devices, character recognition, voice recognition, and improvements in computer speed and memory size, the keyboard remains the most commonly used and most versatile device used for direct human input into computers.

http://en.wikipedia.org/wiki/Alphanumeric_keyboard