Computer keyboard

In computing, a computer keyboard is a typewriter-style device which uses an arrangement of buttons or keys to act as a mechanical lever or electronic switch. Following the decline of punch cards and paper tape, interaction via teleprinter-style keyboards became the main input device for computers.

A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or execute computer commands.

Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used device for direct (human) input of alphanumeric data into computers.

In normal usage, the keyboard is used as a text entry interface to type text and numbers into a word processor, text editor or other programs. In a modern computer, the interpretation of key presses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all key presses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations. A keyboard is also used to give commands to the operating system of a computer, such as Windows' Control-Alt-Delete combination, which brings up a task window or shuts down the machine. A command-line interface is a type of user interface operated entirely through a keyboard, or another device doing the job of one.

Keyboard

Keyboard may refer to:

Typing

Music

Musical keyboard

A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the interval of an octave. Depressing a key on the keyboard causes the instrument to produce sounds, either by causing a hammer to mechanically strike a string or tine (piano, electric piano, clavichord); pluck a string (harpsichord); open a valve to let air flow through a pipe (pipe organ or accordion); or strike a bell (carillon in a church tower). On electric and electronic keyboards, depressing a key connects one or several circuits (Hammond organ, digital piano, synthesizer, MIDI controller keyboard) which causes sounds to be produced. A pedal keyboard is a keyboard used with a pipe organ or theatre organ which is played with the feet. Since the most commonly encountered keyboard instrument is the piano, the keyboard layout is often referred to as the "piano keyboard".

Apple Keyboard

The Apple Keyboard is a keyboard designed by Apple Inc. first for the Apple line, then the Macintosh line of computers. Dozens of models have been released over time, including the Apple Extended Keyboard. There are currently two keyboards offered by Apple: a full-sized version using USB, and the Apple Magic Keyboard, which connects via Bluetooth and omits the numeric keypad of the full-sized model. Both share a similar look and feel, based on a very thin aluminum chassis and laptop-style low-profile keys, sitting much closer to the tabletop than traditional keyboard designs.

Layout

To serve the functionality of the Mac OS (and because of historical differences), the Apple Keyboard's layout differs somewhat from that of the ubiquitous IBM PC keyboard, mainly in its modifier and special keys. Some of these keys have unique symbols defined in the Unicode block Miscellaneous Technical. Features different from other keyboards include: