Fn, or 'Function,' is a modifier key on many keyboards, especially on laptops, used in a compact layout to combine keys which are usually kept separate. It is typically found on laptops, since a full sized keyboard would be difficult to fit in a laptop chassis. It is also found in many full-sized 'multimedia' and 'office' keyboards, named F Lock key. It is mainly for the purpose of changing display or audio settings quickly, such as brightness, contrast, or volume, and is held down in conjunction with the appropriate key to change the settings.
Compact layouts
Typically, in a compact layout the main area of the keyboard (containing the letter keys) is kept in much the same layout as with a full-sized keyboard, and the numeric keypad is moved to share a group of central keys. This allows typists to enter text without having to learn a new layout. The symbol that is accessed through pressing Fn is often printed on the key in a smaller font or different colour (usually blue).
This 78-key UK layout is taken from the Apple iBook. Characters in blue are accessed through the Fn key, but functions on the top row can be accessed without Fn key in Mac OS X.
Technical details
Unlike other modifier keys such as Shift or AltGr, the control processor inside the keyboard typically sends out a different keycode depending on whether the Fn key is depressed. This allows the keyboard to emulate a full sized keyboard and means that specialised keymaps do not need to be created; the operating system can use standard keymaps designed for a full sized keyboard. This also means that software-remapping of the Fn-key to another key or vice versa is impossible.
In addition to being mapped to standard keyboard keys like Scroll Lock and Num Lock, the Fn key combinations may also be mapped to control system interfaces to change the LCD brightness, VGA output, or speaker volume on most laptop computers.
In many designs, pressing F-Lock or Fn key itself does not generate a scancode.
Displacement of the Control key
The Fn key is usually placed either to the right or to the left of the left Control key. In the latter case, it displaces the control key from the lower left corner of the keyboard. This is where the control key sits on keyboards without the Fn key, and such an arrangement causes considerable user confusion when switching to and from normal full-size keyboards.[1]
Apple keyboards
Newer Apple Keyboards have an Fn key that modifies the function of the function keys from those printed to a normal function key.
External links
References
- ^ http://www.ashbaughonline.com/2006/08/12/thinkpad-fn-ctrl-key/
