The IBM PC keyboard and its derivative computer keyboards are standardized. However, during the 20 years of the PC architecture being constantly updated, several types of keyboards have been developed. IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ... A computer keyboard is a peripheral partially modeled after the typewriter keyboard. ...

[edit] Keyboard layouts

The following list gives a concise overview of the PC keyboard as it has changed over the years, the changes often being made at the launch of new PC versions. For each layout, some of the most significant updates are mentioned.

•   83-key   PC/XT keyboard layout – original left hand side function key (F key) columns with 10 keys F1 through F10; electronically not compatible with the later keyboard types.
•   84-key   PC/AT keyboard layout – the "84th key" being <SysRq> i.e. System Request; numerical block now clearly separated from main keyboard; also added indicator LEDs for Caps/Scroll/Num lock.
• 101-key "Enhanced" keyboard layout – additional navigation and control keys; 12 F keys in row along top, grouped F1-4, F5-8, and F9-12.
• 102-key "Enhanced" keyboard layout – (additional key to the right of the left Shift key for European layouts)
• 106-key "Enhanced" keyboard layout – 5 more keys added for input in Asian languages.
• 104-key "Windows" keyboard layout – Windows(x2) and Menu key added.
• 105-key as above, but for European layouts.
• 109-key as above, but for Asian layouts.
• 107-key "Enhanced" keyboard layout – Power management keys were added.

So-called "multimedia keyboards" may offer additional buttons to the 104 or 107 "standard" keys, often providing volume control, media player buttons, and miscellaneous user-configurable shortcuts, e.g. to email clients, web browsers, etc. The IBM XT, somewhat more formally known as the PC XT or PC/XT, was IBMs successor to the original IBM PC. It was released on March 8, 1983, and was one of the first computers to come standard with a hard drive. ... A function key is a key on a computer or terminal keyboard which can be programmed so as to cause an operating system command interpreter or application program to perform certain actions. ... The term compatibility has the following meanings: In telecommunication, the capability of two or more items or components of equipment or material to exist or function in the same system or environment without mutual interference. ... The IBM PC/AT was IBMs third-generation PC, designed around the Intel 80286 microprocessor and released in 1984. ... A 102-key PC US English keyboard layout with the SysRq key outlined in red. ... Blue, green and red LEDs. ... A Windows key on a black laptop keyboard The Windows key or Windows logo key (in short WinKey, or rarely Flag key) is a keyboard key originally introduced for the Windows 95 operating system. ... In computing, the Menu key is a key found on Windows-oriented computer keyboards. ... Power management keys placed in the top row, with the keys at that place and below moved down one row. ... ...

[edit] Standard key meanings

The PC keyboard with its various keys has a long history of evolution reaching back to teletypewriters. In addition to the 'old' standard keys, the PC keyboard has accumulated several special keys over the years. Some of the additions have been inspired by the opportunity or requirement for improving user productivity with general office application software, while other slightly more general keyboard additions have become the factory standards after being introduced by certain operating system or GUI software vendors such as Microsoft. Teletype machines in World War II A teleprinter (teletypewriter, teletype or TTY for TeleTYpe/TeleTYpewriter) is a now largely obsolete electro-mechanical typewriter which can be used to communicate typed messages from point to point through a simple electrical communications channel, often just a pair of wires. ... This article or section does not cite any references or sources. ... // An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. ... A graphical user interface (GUI) is a type of user interface which allows people to interact with a computer and computer-controlled devices which employ graphical icons, visual indicators or special graphical elements called widgets, along with text labels or text navigation to represent the information and actions available to... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ...

See also: modifier key In computing, a modifier key is a special key on a computer keyboard that modifies the normal action of another key when the two are pressed in combination. ...

[edit] From mechanical typewriters

• Shift selects the upper character, or select upper case of letters. The Shift key in typewriters was attached to a lever that moved the character types so that the uppercase characters could be printed in the paper. Unlike mechanical typewriters, PC keyboards do not capitalize all letters properly when both shift keys are engaged simultaneously.
• Caps Lock selects upper case, or if shift is pressed, lower case of letters. In mechanical typewriters, it worked like the Shift key, but also used a lock to keep the Shift key depressed. The lock was released by pressing the Shift key.
• Enter wraps to the next line or activates the default or selected option. ASCII keyboards were labeled CR or Return. Typewriters used a lever that would return the cylinder with the paper to the start of the line.

The shift key on a modern Windows keyboard The shift key is a modifier key on a keyboard, used to type capital letters and other alternate upper characters. ... The caps lock on a modern Windows keyboard. ... Originally, carriage return was the term for the key, lever, or mechanism on a typewriter that would cause the cylinder on which the paper was held (the carriage) to return to the left side of the paper after a line of text had been typed, and would often move it...

[edit] From Teletype keyboards

• Ctrl shifts the value of letters and numbers from the ASCII graphics range, down into the ASCII control characters. For example, CTRL-S is XOFF (stops many programs as they print to screen) CTRL-Q is XON (resume printing stopped by CTRL-S).
• Esc produces an ASCII escape character. It may be used to exit menus or modes.
• Tab produces an ASCII Tab character. Moves to the next tab stop.
• ~ is the tilde, an accent backspaced and printed over other letters for non-English languages. Nowadays the key does not produce a backspaceable character and is used for 'not' or 'circa'.
• ` is a grave accent or backtick, also formerly backspaced over letters to write non-English languages; on some systems it is used as an opening quote. The single quote ' is normally used for an acute accent.
• ^ is a circumflex, another accent for non-English languages. Also used to indicate exponentiation where superscript is not available.
• * is an asterisk, used to indicate a note, or multiplication.
• _ is an underscore, backspaced and overprinted to add emphasis.
• | is a vertical bar, originally used as a typographic separator for optical character recognition. Many character sets break it in the middle so it cannot be confused with the numeral "1" or the letter "l". This character is often known as a pipe.

For a list of keyboard shortcuts see Table of keyboard shortcuts A Control key (marked Ctrl) on a modern Windows keyboard In computing, a Control key is a key which, when pressed in conjunction with another key, will perform a special operation. ... Image:ASCII fullsvg There are 95 printable ASCII characters, numbered 32 to 126. ... The Esc key is a key labeled Esc or Escape that is used to generate the ASCII Escape character, the character code traditionally used to initiate an escape sequence. ... In computing and telecommunication, an escape character is one which has a special meaning in a sequence of characters. ... This article is about the use of the term Tab in computing. ... A tilde. ... The grave accent ( ` ) is a diacritic mark used in written Greek until 1982 (polytonic orthography), French, Catalan, Welsh, Italian, Vietnamese, Scottish Gaelic, Norwegian, Portuguese and other languages. ... The circumflex ( ˆ ) (often called a caret, a hat or an uppen) is a diacritic mark used in written Greek, French, Dutch, Esperanto, Norwegian, Romanian, Slovak, Vietnamese, Japanese romaji, Welsh, Portuguese, Italian, Afrikaans and other languages, and formerly in Turkish [citation needed]. It received its English name from Latin circumflexus (bent... This article refers to the typographical symbol. ... The underscore _ is the character with ASCII value 95. ... Vertical bar, verti-bar, vertical line, divider line, or pipe is the name of the character (|). Broken bar (¦) is a separate character. ...

[edit] Invented for the PC

• The Windows key (also known as the super key) is a quick way to open the Start menu in Windows' standard Explorer shell, and can usually be configured to behave similarly in other graphical user interfaces, for Windows and other operating systems.
• The menu key brings up a context menu, similar to right-clicking.
• Function keys are the numbered keys, use varies by program, but F1 is often "help."
• Arrow keys move on the screen. When shifted, they select items.
• Home moves to the start of text, usually the left side of the screen.
• End moves to the end of text, usually the right-most edge of the current line.
• PgUp and PgDn move through the document by pages.
• Delete deletes the character before the screen position, or the selected items.
• Insert toggles between "insertion" and "overwrite" mode.
• Print screen originally printed a text image of the screen; nowadays often takes a screenshot. In combination with Alt, it produces a different keycode, SysRq.
• Num lock toggles between states for the numeric keypad. When off, it acts as arrow and navigational keys. When on, it is a 10-key pad similar to a standard calculator. Preferences vary so much that a favorite default for this key can often be configured in the BIOS configuration. Its continued existence on keyboards that separate out the arrow keys has mostly historical reasons.
• Scroll lock is little-used. On modern software, typing text usually causes earlier text to scroll off the top of the screen or window. Some old programs could disable this and restart at the top of the window when scroll lock was pressed. The advantage is that the entire screen full of text does not shift, making it easier to read. It was also used to lock the cursor on its line and scroll the work area under it. On spreadsheets such as Microsoft Excel, it locks the cell pointer on the current cell, allowing the user to use the arrow keys to move the view window around without moving the cell pointer. On some consoles, it prevents scrolling of messages until another key combination is pressed (such as the Linux console).
• Pause pauses either output or processing. In combination with Control, it produces a different keycode, for Break. Ctrl-Break traditionally stopped programs in DOS. Ctrl-Break is also used to halt execution of the debugger in some programming environments such as Microsoft Visual Studio. In combination with the Windows key, it brings up the System Properties window in Microsoft Windows environments.
• Alt shifts the letters and numbers into the range above hex 0x80 where the international characters and special characters exist in the PC's standard character set. Alt plus a number typed on the numeric pad produces special characters, see Windows Alt keycodes.
• AltGr works like the Ctrl+Alt key combination, often used in combination with other keys to print special characters like the backslash on non-english keyboards.
• Fn may be present on compact keyboards such as those built into laptop computers. When depressed in combination with other keys, it either enables the user to access key functions that do not have dedicated keys on the compact keyboard (such as the numeric block), or it controls hardware functions such as switching between the built-in screen and an external display, changing screen brightness, or changing speaker volume. These alternate meanings are usually indicated with text or symbols of a different color printed on the key, with the 'Fn' key text having that same color.

A Windows key on a black laptop keyboard The Windows key or Windows logo key (in short WinKey, or rarely Flag key) is a keyboard key originally introduced for the Windows 95 operating system. ... This article or section does not cite its references or sources. ... In computing, the Menu key is a key found on Windows-oriented computer keyboards. ... A function key is a key on a computer or terminal keyboard which can be programmed so as to cause an operating system command interpreter or application program to perform certain actions. ... Arrow keys Arrow keys are buttons on a computer keyboard that move the cursor in a specified direction. ... The home key among other keys The home key is a key commonly found on computer keyboards. ... The end key among other keys The end key is a key commonly found on computer keyboards. ... The page scroll keys among other keys The page scroll keys are two keys commonly found on computer keyboards, the page up key and the page down key. ... The user pressing the delete key on a Macintosh On computer keyboards, the delete key (sometimes shortened Del), should, during normal text editing, discard the character at the cursors position, moving all following characters one position back towards the freed place. ... The Insert key (often abbreviated to INS) commonly found on keyboards is mostly used to switch between the two main modes of entering text on a computer. ... A 102-key PC US English keyboard layout with the print screen key marked in red. ... A 102-key PC US English keyboard layout with the SysRq key outlined in red. ... Num Lock is a key on the numeric keypad of most keyboards, used to switch that pad between number entry and arrow keys. ... This is a disambiguation page &#8212; a navigational aid which lists other pages that might otherwise share the same title. ... Scroll lock is a key (with an associated status light) on most modern computer keyboards. ... This article or section does not adequately cite its references or sources. ... Linux (IPA pronunciation: ) is a Unix-like computer operating system. ... Break/Pause key on PC keyboard The break key is a special key on computer keyboards that no longer has a well-defined purpose. ... The Alt key on a modern Windows keyboard The Alt key on an IBM PC keyboard is the key located immediately to either side of the Space bar, used to change (alternate) the function of other pressed keys. ... In PCs running the Microsoft Windows operating system, additional characters to those available by the current keyboard layout may be typed using the Alt key in conjunction with the keyboards numeric pad. ... AltGr is a modifier key on PC keyboards used to type many characters, primarily ones that are unusual for the locale of the keyboard layout, such as foreign currency symbols and accented letters. ... First introduced in 1960 by Bob Bemer, the backslash, , is a typographical mark (glyph) used chiefly in computing. ... Fn key can also refer to the function keys on a computer keyboard. ...

[edit] Connectors

There are three types of connector used to connect a PC keyboard to the main system unit. All three are mechanically different from each other, but the first two are electrically identical (except for XT keyboards, which used a connector mechanically identical to the later AT connector, but not electrically compatible with it). The three connector types are listed below in chronological order: Look up connector in Wiktionary, the free dictionary. ...

• 5-pin DIN (DIN 41524) "AT" connector.
• 6-pin Mini-DIN (DIN 45322) "PS/2" connector.
• 4-pin USB connector.

5 pin 180° DIN connector 4 pin Mini-DIN S-Video connector Speaker DIN line socket (left) and plug DIN connectors are multi-pin electrical connectors based on a DIN standard. ... The mini-DIN connectors are a family of multi-pin Electrical connectors used in a variety of applications. ... The PS/2 connector is used for connecting a keyboard and a mouse to a PC compatible computer system. ... Universal Serial Bus (USB) is a serial bus standard to interface devices. ...

[edit] See Also

• Apple keyboard

This article or section does not cite its references or sources. ...

[edit] External links

• Standard keyboard layouts – From The PC Guide website
• IBM.com keyboard page
• The PS/2 Keyboard Interface
• Key re-mapping software:-
  • SharpKeys: free
  • KeyTweak: free