AltGr key
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. If a key has a third symbol on it (on the front vertical face or the bottom right of the key top, sometimes in a different colour), then AltGr can often be used to type that symbol.
Even though the meaning of "AltGr" is unclear to most people, including many computer experts, IBM unequivocally says that it is an
abbreviation for "alternate graphic" [
1] [
2]. The meaning of the key's abbreviation is not explicitly given in many IBM PC compatible technical reference manuals.
Opinions
The majority's opinion (as shown by Google results on informed pages) seems to support the IBM claim, but some informed pages claim that AltGr means "alternative graphic". Nevertheless, the meaning of the
Alt key seems to always be given as "alternate", e.g. in
Webopedia. Although some claim that the specific function of the AltGr key has never had much to do with graphics (even with "graphics characters"),
an apparently well informed source claims that the meaning might be a holdover from the days of machines like the
Commodore 64, in which holding down some special modifier key and a letter would print a graphical symbol, such as a box-drawing element.
Originally, US PC keyboards (specifically: the US 101-key PC/AT keyboards) did not have an AltGr key, it being only relevant to non-US markets; they simply had "left" and "right"
Alt keys. As those using such US keyboards increasingly needed the specific functionality of AltGr when typing non-English text,
Windows began to allow all keystroke combinations involving AltGr to be typed by using Ctrl+Alt in its place. Therefore, it is recommended that Ctrl-Alt not be used as a modifier in Windows keyboard shortcuts as, depending on the keyboard layout and configuration, someone trying to type a special character with Ctrl-Alt may accidentally trigger the shortcut [
3], or the keypresses for the shortcut may be inadvertently interpreted as the user trying to input a special character.
The function and usage of AltGr vary according to the exact keyboard layout, which in turn varies according to both the locale and the
operating system. On German keyboards it is used to type the symbols {, [, ], and }, which are commonly used by programmers and technical writers.
On those keyboard layouts having a defined AltGr key, it is equivalent to holding down the
Ctrl and
Alt keys together, which means many
Microsoft Windows keyboard shortcuts (for example, shortcuts to icons in
Windows Explorer) can be operated using only one hand from either side of the keyboard.
Finally, AltGr also provides access to special keyboard characters such as the
Euro symbol.
US international
|
US international keyboard layout |
On US international keyboard layouts, the AltGr key can be used to enter the following characters:
¡ ² ³ ¤ € ¼ ½ ¾ ‘ ' ¥ ×
ä å é ® þ ü ú í ó ö « »
á ß ð ø ¶ ´ ¬
æ © ñ µ ç ¿
And, in combination with the Shift key:
¹ £ ÷
Ä Å É Þ Ü Ú Í " Ö
Á § Ð Ø ° ¨ ¦
Æ ¢ Ñ Ç
Note that a lot of these symbols can also be entered using the dead keys.
For comparison, the US international keyboard layout follows. Note that the "`/~" key has been omitted; it does not react to the AltGr key.
1 2 3 4 5 6 7 8 9 0 - =
Q W E R T Y U I O P [ ]
A S D F G H J K L ; ' \
m Z X C V B N M , . /
"m" denotes the "Macro" key. It generally produces a "\", although applications receive a different keycode and can therefore instead use the key to for example run macros.
The functionality of AltGr is also available via Ctrl+Alt. This is useful in case the keyboard is not able to differentiate between the Alt key on the left and the AltGr key on the right.
UK
In UK keyboard layouts, the only two symbols which require the AltGr key are:
*
€ the
Euro currency symbol. Located on the "4/$" key.
* Either
|, the
vertical bar ("pipe symbol") or
¦, the broken vertical bar ("broken pipe symbol"). Located on the "`/¬" key, to the immediate left of "1".
The two latter symbols interchange places in UK keyboards according to the
operating system in use. In
OS/2, the "UK keyboard layout" (specifically: the UK166 layout) requires AltGr for the vertical bar and the broken vertical bar is a shifted key — which, coincidentally, matches the actual symbols that are printed on most UK keyboards; in
Windows, the "UK keyboard layout" requires AltGr for the broken vertical bar and the vertical bar is a shifted key — the converse of what is usually printed on the keys; and in
Linux, the "UK keyboard layout" does not have a simple keystroke combination for the broken vertical bar at all, producing the vertical bar for both key combinations.
In the
X Window System, AltGr can be used to produce additional characters with almost every key in the keyboard. AltGr+Shift+Q produces
Ω, AltGr[+Shift]+O produces
Ø/
ø, AltGr+M produces
µ, and so on. With some keys, AltGr produces a
dead key; for example on a
UK keyboard AltGr+; produces a combining acute accent, thus AltGr+; followed by e produces
é.
Modified keys tables
The keymap with the
Alt Gr key:
@ ł € ® þ ← " ' " þ " ~ ª ß ð đ ŋ ħ j ĸ ł ' ^ ˝
\ « » © " " n µ ¸ ·
The keymap with
Alt Gr+Shift:
Ω Ł ¢ ® Þ ¥ ↑ ı ' Þ ˚ ˇ º § Ð ª Ŋ Ħ J & Ł ˝ ˇ ×
¬ < > © ` ' N º ˛ ˙ ˙
Notice: These examples are used upon a Danish keymap, so here is a Danish keymap for reference: q w e r t y u i o p å ¨ a s d f g h j k l æ ø '
< z x c v b n m , . -
*
Keyboard layout*
Modifier key*
Alt key
