CODE PAGE 437

IBM PC or MS-DOS 'code page 437', often abbreviated 'CP437' and also known as, 'DOS-US', 'OEM-US' or sometimes misleadingly as just the 'OEM font', 'High ASCII' or 'Extended ASCII'[1][2], is the original character set of the IBM PC, circa 1981.

Contents
Characters
Difference from ASCII
See also
External links
References

Characters


The following is a table representing CP437 using the equivalent Unicode characters:
.0 .1 .2 .3 .4 .5 .6 .7 .8 .9 .A .B .C .D .E .F

'''0'''
'''1'''
'''2'''
'''3'''
'''4'''
'''5'''
'''6'''
'''7'''
'''8'''
'''9'''
'''10'''
'''11'''
'''12'''
'''13'''
'''14'''
'''15'''

'''16'''
'''17'''
'''18'''
'''19'''
'''20'''
'''21'''
'''22'''
'''23'''
'''24'''
'''25'''
'''26'''
'''27'''
'''28'''
'''29'''
'''30'''
'''31'''

'''32'''
'''33'''
'''34'''
'''35'''
'''36'''
'''37'''
'''38'''
'''39'''
'''40'''
'''41'''
'''42'''
'''43'''
'''44'''
'''45'''
'''46'''
'''47'''

'''48'''
'''49'''
'''50'''
'''51'''
'''52'''
'''53'''
'''54'''
'''55'''
'''56'''
'''57'''
'''58'''
'''59'''
'''60'''
'''61'''
'''62'''
'''63'''

'''64'''
'''65'''
'''66'''
'''67'''
'''68'''
'''69'''
'''70'''
'''71'''
'''72'''
'''73'''
'''74'''
'''75'''
'''76'''
'''77'''
'''78'''
'''79'''

'''80'''
'''81'''
'''82'''
'''83'''
'''84'''
'''85'''
'''86'''
'''87'''
'''88'''
'''89'''
'''90'''
'''91'''
'''92'''
'''93'''
'''94'''
'''95'''

'''96'''
'''97'''
'''98'''
'''99'''
'''100'''
'''101'''
'''102'''
'''103'''
'''104'''
'''105'''
'''106'''
'''107'''
'''108'''
'''109'''
'''110'''
'''111'''

'''112'''
'''113'''
'''114'''
'''115'''
'''116'''
'''117'''
'''118'''
'''119'''
'''120'''
'''121'''
'''122'''
'''123'''
'''124'''
'''125'''
'''126'''
'''127'''

'''128'''
'''129'''
'''130'''
'''131'''
'''132'''
'''133'''
'''134'''
'''135'''
'''136'''
'''137'''
'''138'''
'''139'''
'''140'''
'''141'''
'''142'''
'''143'''

'''144'''
'''145'''
'''146'''
'''147'''
'''148'''
'''149'''
'''150'''
'''151'''
'''152'''
'''153'''
'''154'''
'''155'''
'''156'''
'''157'''
'''158'''
'''159'''

'''160'''
'''161'''
'''162'''
'''163'''
'''164'''
'''165'''
'''166'''
'''167'''
'''168'''
'''169'''
'''170'''
'''171'''
'''172'''
'''173'''
'''174'''
'''175'''

'''176'''
'''177'''
'''178'''
'''179'''
'''180'''
'''181'''
'''182'''
'''183'''
'''184'''
'''185'''
'''186'''
'''187'''
'''188'''
'''189'''
'''190'''
'''191'''

'''192'''
'''193'''
'''194'''
'''195'''
'''196'''
'''197'''
'''198'''
'''199'''
'''200'''
'''201'''
'''202'''
'''203'''
'''204'''
'''205'''
'''206'''
'''207'''

'''208'''
'''209'''
'''210'''
'''211'''
'''212'''
'''213'''
'''214'''
'''215'''
'''216'''
'''217'''
'''218'''
'''219'''
'''220'''
'''221'''
'''222'''
'''223'''

'''224'''
'''225'''
'''226'''
'''227'''
'''228'''
'''229'''
'''230'''
'''231'''
'''232'''
'''233'''
'''234'''
'''235'''
'''236'''
'''237'''
'''238'''
'''239'''

'''240'''
'''241'''
'''242'''
'''243'''
'''244'''
'''245'''
'''246'''
'''247'''
'''248'''
'''249'''
'''250'''
'''251'''
'''252'''
'''253'''
'''254'''
'''255'''
.0.1.2.3.4.5.6.7.8.9.A.B.C.D.E.F

Difference from ASCII


It is based on ASCII, with the following modifications:

★ The C0 control range (0x00–0x1F hex) is mapped to graphics characters. The codes can assume their original function as controls, but when placed in display RAM and then viewed in text mode, for example in a screen editor like MS-DOS edit, they show as graphics. The graphics are various, such as smiling faces, card suits and musical notes. Code 0x7F, DEL, similarly shows as a graphic (a house).

★ The high-bit range, 0x80–0xFF, is mapped to various symbols: a few European characters (accented Latin vowels, etc) in no particular order and not sufficient for representation of most Western European languages, box drawing characters, mathematical symbols and a few Greek letters commonly used in mathematics and physics.
The repertoire of CP437 was taken from the character set of Wang word-processing machines, according to Bill Gates in an interview with Gates and Paul Allen that in the 2nd of October 1995 edition of Fortune Magazine:
: "… we were also fascinated by dedicated word processors from Wang, because we believed that general-purpose machines could do that just as well. That's why, when it came time to design the keyboard for the IBM PC, we put the funny Wang character set into the machine—you know, smiley faces and boxes and triangles and stuff. We were thinking we'd like to do a clone of Wang word-processing software someday."
CP437 is inadequate for internationalisation, as it lacks characters necessary for some languages, such as À (capital A with grave) for French, and has only a few Greek letters. Later MS-DOS character sets, such as CP850 (DOS Latin-1), CP852 (DOS Central-European) and CP737 (DOS Greek), filled the gaps for international use while still being nearly compatible with CP437 by retaining most of the box-drawing characters. All CP437 characters are in Unicode and in Microsoft's WGL4 character set, therefore in most of the fonts on Microsoft Windows, and also in the default VGA font of the Linux kernel, and the ISO 10646 fonts for X11.
Implementors of mapping tables to Unicode should note that CP437 unifies some characters that look almost the same (to the eyes of its implementors, not to the eyes of a typographer): 0xE1 is both the German sharp S (U+00DF, ß) and the Greek lowercase beta (U+03B2, β); 0xE4 is both the n-ary summation sign (U+2211, ∑) and the Greek uppercase sigma (U+03A3, Σ); 0xE6 is both the micro sign (U+00B5, µ) and the Greek lowercase mu (U+03BC, μ); 0xEA is both the ohm sign (U+2126, Ω) and the Greek uppercase omega (U+03A9, Ω) (note that in Unicode as well, the ohm sign is canonically equivalent to the capital omega, and its use is discouraged in favor of capital omega[1]); and 0xEE is both the element-of sign (U+2208, ∈) and the Greek lowercase epsilon (U+03B5, ε).
In DOS and Windows, most characters from the currently active can be inserted by holding down the Alt key and entering the character's three-digit decimal code on the numpad. Which DOS code page is currently active can be found out by querying mode.com. This technique is called ''Windows Alt keycodes''.

See also



★ ASCII

★ ASCII art

★ ANSI art

★ Western Latin character sets (computing)

External links



★ Microsoft Code Page 437 reference chart

References


1. http://www.cdrummond.qc.ca/cegep/informat/Professeurs/Alain/files/ascii.htm
2. http://www.pcmag.com/encyclopedia_term/0,2542,t=OEM+font&i=48292,00.asp


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