Alt codes
Encyclopedia
On personal computer
s running the Microsoft Windows
or DOS
operating system
s, additional character
s to those available in the current keyboard layout
can be typed using an Alt code: pressing and holding the Alt key
while entering a character code with the keyboard's numeric keypad
. Laptop keyboards often do not have a numpad, but may provide numpad input by holding a modifier key (typically labelled "Fn"); thus one must press and hold both Alt and Fn keys while entering the character code.
Often this is the best or only method many computer users know for entering non-ASCII characters. Due to its popularity, the input method has been duplicated, including the use of obsolete code pages, to other operating systems. Many Wikipedia articles on various characters will include how to type that character using Alt codes for code page 437
.
. For systems using English, this is code page 437
. For most other systems using the Latin alphabet, this is code page 850
. For a complete list, see code page
.
These numbers became so well known and memorized by computer users that Microsoft was forced to preserve them when it transitioned Windows to use the Windows-1252
and similar international sets. Holding Alt and typing a leading 0 (zero) and then a number would produce the character from the Windows code page
. If there was no leading zero, an attempt was made to translate the code from CP437 to the matching glyph in the Windows code page.
For instance, the combination +0161 yields the character "¡" (Windows-1252), while the combination +161 yields "í" (the glyph
for Latin letter i with acute accent) (CP850).
When Windows transitioned to Unicode the same thing had happened: the 0-leading codes had become so well known that a third method needed to be invented to produce Unicode code points, though it was somewhat mitigated by Unicode matching CP1252. The full-legacy Alt codes with no leading zero became more reliable as all glyphs in the legacy code pages had matching glyphs in Unicode. The following method can be used on Microsoft Windows
to enter any Unicode codepoint as a hexadecimal number:
is disabled, attempting an Alt code may cause unexpected results in some applications. For example, Alt+4 can be taken as Alt+Left Arrow, causing a web browser to go back one page.
Many laptops do not have a separate numeric keypad; however, the Fn key can be used to turn certain keys into a numeric keypad. There usually is a key called [Num lock] to ‘shift’ certain keys to act as if they were the numeric keypad keys. For example, in laptops sold in Spain
, the following scheme is very common:
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
s running the Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
or DOS
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s, additional character
Character (computing)
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....
s to those available in the current keyboard layout
Keyboard layout
A keyboard layout is any specific mechanical, visual, or functional arrangement of the keys, legends, or key–meaning associations of a computer, typewriter, or other typographic keyboard....
can be typed using an Alt code: pressing and holding the Alt key
Alt key
The Alt key on a computer keyboard is used to change the function of other pressed keys. Thus, the Alt key is a modifier key, used in a similar fashion to the Shift key. For example, simply pressing "A" will type the letter a, but if you hold down either Alt key while pressing A, the computer...
while entering a character code with the keyboard's numeric keypad
Numeric keypad
A numeric keypad, numpad or tenkey for short, is the small, palm-sized, seventeen key section of a computer keyboard, usually on the very far right. The numeric keypad features digits 0 to 9, addition , subtraction , multiplication and division symbols, a decimal point and Num Lock and Enter keys...
. Laptop keyboards often do not have a numpad, but may provide numpad input by holding a modifier key (typically labelled "Fn"); thus one must press and hold both Alt and Fn keys while entering the character code.
Often this is the best or only method many computer users know for entering non-ASCII characters. Due to its popularity, the input method has been duplicated, including the use of obsolete code pages, to other operating systems. Many Wikipedia articles on various characters will include how to type that character using Alt codes for code page 437
Code page 437
IBM PC or MS-DOS code page 437 is the character set of the original IBM PC. It is also known as CP 437, OEM 437, PC-8, MS-DOS Latin US or sometimes misleadingly referred to as the OEM font, High ASCII or Extended ASCII....
.
History and description
Originally in MS-DOS, the user could hold down the Alt key and type a decimal number on the keypad. The BIOS would turn this directly into the character code of the same value, which (if the program did not interpret as a command) would place that same code on the screen, thus displaying that character from the current code pageCode page
Code page is another term for character encoding. It consists of a table of values that describes the character set for a particular language. The term code page originated from IBM's EBCDIC-based mainframe systems, but many vendors use this term including Microsoft, SAP, and Oracle Corporation...
. For systems using English, this is code page 437
Code page 437
IBM PC or MS-DOS code page 437 is the character set of the original IBM PC. It is also known as CP 437, OEM 437, PC-8, MS-DOS Latin US or sometimes misleadingly referred to as the OEM font, High ASCII or Extended ASCII....
. For most other systems using the Latin alphabet, this is code page 850
Code page 850
Code page 850 is a code page used under MS-DOS in Western Europe. It is the code page commonly used by the version of MS-DOS underlying Windows ME...
. For a complete list, see code page
Code page
Code page is another term for character encoding. It consists of a table of values that describes the character set for a particular language. The term code page originated from IBM's EBCDIC-based mainframe systems, but many vendors use this term including Microsoft, SAP, and Oracle Corporation...
.
These numbers became so well known and memorized by computer users that Microsoft was forced to preserve them when it transitioned Windows to use the Windows-1252
Windows-1252
Windows-1252 or CP-1252 is a character encoding of the Latin alphabet, used by default in the legacy components of Microsoft Windows in English and some other Western languages. It is one version within the group of Windows code pages...
and similar international sets. Holding Alt and typing a leading 0 (zero) and then a number would produce the character from the Windows code page
Windows code page
Windows code pages are sets of characters or code pages used in Microsoft Windows from the 1980s and 1990s...
. If there was no leading zero, an attempt was made to translate the code from CP437 to the matching glyph in the Windows code page.
For instance, the combination +0161 yields the character "¡" (Windows-1252), while the combination +161 yields "í" (the glyph
Glyph
A glyph is an element of writing: an individual mark on a written medium that contributes to the meaning of what is written. A glyph is made up of one or more graphemes....
for Latin letter i with acute accent) (CP850).
When Windows transitioned to Unicode the same thing had happened: the 0-leading codes had become so well known that a third method needed to be invented to produce Unicode code points, though it was somewhat mitigated by Unicode matching CP1252. The full-legacy Alt codes with no leading zero became more reliable as all glyphs in the legacy code pages had matching glyphs in Unicode. The following method can be used on Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
to enter any Unicode codepoint as a hexadecimal number:
- Set the registry key
HKCU\Control Panel\Input Method\EnableHexNumpadto type REG_SZ and value 1 and reboot. - Keep the Alt key pressed. Press the "+" key on the numeric keypad.
- With the Alt key still pressed, type the hexadecimal number using the numeric keypad for digits 0-9 and the normal keys for a-f. For example, type +11b to produce ě (e with caron).
Problems
If Num LockNum lock
Num Lock is a key on the numeric keypad of most computer keyboards. It is a toggle key, like Caps Lock and Scroll Lock. Its state is commonly represented by an LED light built into the keyboard....
is disabled, attempting an Alt code may cause unexpected results in some applications. For example, Alt+4 can be taken as Alt+Left Arrow, causing a web browser to go back one page.
Many laptops do not have a separate numeric keypad; however, the Fn key can be used to turn certain keys into a numeric keypad. There usually is a key called [Num lock] to ‘shift’ certain keys to act as if they were the numeric keypad keys. For example, in laptops sold in Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, the following scheme is very common:
| 7 | 8 | 9 | 0 |
| U | I | O | P |
| J | K | L | Ñ |
| M | . | - |
See also
- Compose keyCompose keyA compose key, available on some computer keyboards, is a special kind of modifier key designated to signal the software to interpret the following sequence of two keystrokes as a combination in order to produce a character not found directly on the keyboard...
for other operating systems - Numeric character referenceNumeric character referenceA numeric character reference is a common markup construct used in SGML and other SGML-related markup languages such as HTML and XML. It consists of a short sequence of characters that, in turn, represent a single character from the Universal Character Set of Unicode...
- Unicode inputUnicode inputUnicode input is the insertion of a specific Unicode character on a computer. Unicode characters can be inserted in two ways: from the screen by means of an applet from which one can select the character, or by input of the Unicode character from the keyboard...
- Combining characterCombining characterIn digital typography, combining characters are characters that are intended to modify other characters. The most common combining characters in the Latin script are the combining diacritical marks ....