Code page 437 (CCSID 437) is the character set of the original IBM PC (personal computer).[2] It is also known as CP437, OEM-US, OEM 437,[3] PC-8,[4] or DOS Latin US.[5] The set includes all printable ASCII characters as well as some accented letters (diacritics), Greek letters, icons, and line-drawing symbols. It is sometimes referred to as the "OEM font" or "high ASCII", or as "extended ASCII"[4] (one of many mutually incompatible ASCII extensions).
Code page 437
Code page 437, as rendered by an IBM PC using standard VGA
This character set remains the primary set in the core of any EGA and VGA-compatible graphics card. As such, text shown when a PC reboots, before fonts can be loaded and rendered, is typically rendered using this character set.[note 1] Many file formats developed at the time of the IBM PC are based on code page 437 as well.
All these display adapters have text modes in which each character cell contains an 8-bit character code point (see details), giving 256 possible values for graphic characters. All 256 codes were assigned a graphical character in ROM, including the codes from 0 to 31 that were reserved in ASCII for non-graphical control characters.
Various Eastern European PCs used different character sets, sometimes user-selectable via jumpers or CMOS setup. These sets were designed to match 437 as much as possible, for instance sharing the code points for many of the line-drawing characters, while still allowing text in a local language to be displayed.
Alt codesedit
A legacy of code page 437 is the number combinations used in Windows Alt codes.[6][7][8] A DOS user could enter a character by holding down the Alt key and entering the character code on the numpad[6] and many users memorized the numbers needed for CP437 (or for the similar CP850). Although Microsoft Windows used different character sets such as CP1252, the original numbers were emulated so users could continue to use them; Microsoft added the ability to type a code from the Windows character set by typing 0 before the digits.[6][9]
Character setedit
The following tables show code page 437. Each character is shown with its equivalent Unicode code point (when it is not equal to the character's code). A tooltip, generally available only when one points to the immediate left of the character, shows the Unicode code point name and the decimal Alt code. See also the notes below, as there are multiple equivalent Unicode characters for some code points.
Although the ROM provides a graphic for all 256 different possible 8-bit codes, some APIs will not print some code points, in particular the range 0-31 and the code at 127.[10] Instead, they will interpret them as control characters. For instance, many methods of outputting text on the original IBM PC would interpret hex codes 07, 08, 0A and 0D as BEL, BS, CR and LF, respectively. Many printers were also unable to print these characters.
When translating to Unicode some codes do not have a unique, single Unicode equivalent; the correct choice may depend upon context.
^0 draws a blank space, but usage as the C string terminator means it is more accurately translated as NUL
^Mapping as shown, to the beamed quavers [U+266B, ♫], follows data provided by the Unicode Consortium.[15] In IBM's GCGID (Graphic Character Global IDentifier) system of character IDs, this is SM910000, simply annotated as "Two Musical Notes";[12][13] however, the reference glyph shows two beamed semiquavers [U+266C, ♬].[12] In the specification for IBM Japanese Host code, SM910080 (i.e. SM910000 with the fullwidth attribute set) is explicitly mapped to U+266C, and accordingly shows two semiquavers.[16]
^124 (7Chex) The actual glyph at this position is a broken bar [U+00A6, ¦] in the original IBM PC and compatibles font, as rendered by the original MDA. This rendering was later adopted for CGA, EGA and VGA (see image at the beginning of the article). However, almost all software assumes this code is the ASCII character [U+007C, |]; for example, programming languages use it as "or". In the early 1990s, it was clarified[by whom?] that there is vertical bar in ASCII at this position and that the broken bar symbol is not part of ASCII.
^127 (7Fhex) is a "house" but was also sometimes used as Greek capital delta [U+0394, Δ].
^Could also serve as an integral extension [U+23AE, ⎮] in IBM's font.
^Comparison of characters in the E0 to EF range across various IBM products.225 (E1hex) is identified by IBM as Latin "Sharp s Small"[13] [U+00DF, ß] but is sometimes rendered in OEM fonts as Greek small beta [U+03B2, β]. The placement of this Latin character among Greek characters suggests intended multi-use.
^227 (E3hex) is identified by IBM as Greek "Pi Small" [U+03C0, π] but is sometimes rendered in OEM fonts as Greek capital pi [U+03A0, Π] or the n-aryproduct sign [U+220F, ∏].
^228 (E4hex) is identified by IBM as Greek "Sigma Capital" [U+03A3, Σ] but is also used as the n-arysummation sign [U+2211, ∑].
^230 (E6hex) is identified by IBM as Greek "Mu Small" [U+03BC, μ] but is also used as the micro sign [U+00B5, µ]. In Unicode, IBM's Greek GCGID table[17] maps the character in this code page to the Greek letter, but Python, for example, maps it to the micro sign.
^233 (E9hex) is identified by IBM as Greek "Theta Capital" [U+0398, Θ].[12][13] However, these symbols are for mathematics and physics, in which lowercase theta is much more commonly used (e.g. for polar coordinates).
^234 (EAhex) is identified by IBM as Greek "Omega Capital" [U+03A9, Ω] but is also used as the ohm sign [U+2126, Ω]. Unicode considers the characters to be equivalent and suggests that U+03A9 be used in both contexts.[18]
^235 (EBhex) is identified by IBM as Greek "Delta Small" [U+03B4, δ]. It was also unofficially used for the small eth [U+00F0, ð] and the partial derivative sign [U+2202, ∂]
^237 (EDhex) is identified by IBM as Greek "Phi Small (Closed Form)" [U+03D5, ϕ; or, from the italicized math set, U+1D719, 𝜙] but, in some codecs (e.g. the codec library of Python[19]), is mapped to Unicode as the open (or "loopy") form [U+03C6, φ]. Comparison of IBM's Greek GCGID table[17] with Unicode's Greek code chart[20] shows where IBM, for example, reversed the open and closed forms when mapping to Unicode. This character is also used as the empty set sign [U+2205, ∅], the diameter sign [U+2300, ⌀], and the Latin letter O with stroke [U+00D8, Ø; and U+00F8, ø].
^238 (EEhex) is identified by IBM as Greek "Epsilon Small" [U+03B5, ε] but is sometimes rendered in OEM fonts as the element-of sign [U+2208, ∈]. It was often used as the euro sign [U+20AC, €]
^244 (F4hex) and 245 (F5hex) are the upper and lower portion of the integral symbol (∫), and they can be extended with the character 179 (B3hex), the vertical line of the box drawing block. 244 could also be used for the long s character [U+017F, ſ].
^249 (F9hex) and 250 (FAhex) are almost indistinguishable: the first is a slightly larger dot than the second, both were used as bullets, middle dot, and multiplication dot [U+2219, ∙]
^251 (FBhex) was also sometimes used as a check mark [U+2713, ✓].
^255 (FFhex) draws a blank space; the use as non-breaking space (NBSP) has precedent in word processors designed for the IBM PC.
Historyedit
The repertoire of code page 437 was taken from the character set of Wang word-processing machines, according to Bill Gates in an interview with Gates and Paul Allen that appeared in the 2 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."
According to an interview with David J. Bradley (developer of the PC's ROM-BIOS) the characters were decided upon during a four-hour meeting on a plane trip from Seattle to Atlanta by Andy Saenz (responsible for the video card), Lew Eggebrecht (chief engineer for the PC) and himself.[21]
The selection of graphic characters has some internal logic:
Table rows 0 and 1, codes 0 to 31 (00hex to 1Fhex), are assorted dingbats (complementary and decorative characters). The isolated character 127 (7Fhex) also belongs to this group.
Table rows 2 to 7, codes 32 to 126 (20hex to 7Ehex), are the standard ASCII printable characters.
Table rows 8 to 10, codes 128 to 175 (80hex to AFhex), are a selection of international text characters.
Table rows 11 to 13, codes 176 to 223 (B0hex to DFhex), are box drawing and block characters. This block is arranged so that characters 192 to 223 (C0hex to DFhex) contain all the right arms and right-filled areas. The original IBM PCMDA display adapter stored the code page 437 character glyphs as bitmaps eight pixels wide, but for visual enhancement displayed them every nine pixels on screen. This range of characters had the eighth pixel column duplicated by special hardware circuitry,[22] thus filling in gaps in lines and filled areas. The VGA adapter allows this behaviour to be turned on or off.[23]
Table rows 14 and 15, codes 224 to 254 (E0hex to FEhex) are devoted to mathematical symbols, where the first twelve are a selection of Greek letters commonly used in physics.
Most fonts for Microsoft Windows include the special graphic characters at the Unicode indexes shown, as they are part of the WGL4 set that Microsoft encourages font designers to support. (The monospaced raster font family Terminal was an early font that replicated all code page 437 characters, at least at some resolutions.) To draw these characters directly from these code points, a Microsoft Windows font called MS Linedraw[24] replicates all of the code page 437 characters, thus providing one way to display DOS text on a modern Windows machine as it was shown in DOS, with limitations.[25]
Code page 1055, also known as HP symbol set 0L,[26] is a subset which includes the box-drawing, half-blocks, black circles (the black circle replaces the bullet, which replaces the middle dot in this code page), and black square, and moves them to the upper half; the space is also included.[27]
Internationalizationedit
Code page 437 has a series of international characters, mainly values 128 to 175 (80hex to AFhex). However, it only covers a few major Western European languages in full, including English, German and Swedish,[note 2] and so lacks several characters (mostly capital letters) important to many major Western European languages:
Danish/Norwegian: Ø and ø. Character number 237 (EDhex), the small phi (closed form), could be used as a surrogate even though it may not render well (furthermore, it tends to map to Unicode, and/or render in Unicode fonts, as the open-form phi or the closed-vertical-form phi, which are even further from the O with stroke). To compensate, the Danish/Norwegian and Icelandic code pages (865 and 861) replaced cent sign (¢) with ø and the yen sign (¥) with Ø.
Most Greek alphabet symbols were omitted, beyond the basic math symbols. (They were included in the Greek-language code pages 737 and 869. Some of the Greek symbols that were already in code page 437 had their glyphs changed from mathematical or scientific forms to match the actual use in Greek.)
Along with the cent (¢), pound sterling (£) and yen/yuan (¥) currency symbols, it has a couple of former European currency symbols: the florin (ƒ, Netherlands) and the peseta (₧, Spain). The presence of the last is unusual, since the Spanish peseta was never an internationally relevant currency, and also never had a symbol of its own; it was simply abbreviated as "Pt", "Pta", "Pts", or "Ptas". Spanish models of the IBM electric typewriter, however, also had a single position devoted to it.
Later DOS character sets, such as code page 850 (DOS Latin-1), code page 852 (DOS Central-European) and code page 737 (DOS Greek), filled the gaps for international use with some compatibility with code page 437 by retaining the single and double box-drawing characters, while discarding the mixed ones (e.g. horizontal double/vertical single). All code page 437 characters have similar glyphs in Unicode and in Microsoft's WGL4 character set, and therefore are available in most fonts in Microsoft Windows, and also in the default VGA font of the Linux kernel, and the ISO 10646 fonts for X11.
^Systems available in Eastern European, Arabic, and Asian countries often use a different set; however, these sets are designed to match 437 as much as possible. The designation "OEM", for "original equipment manufacturer", indicates that the set could be changed by the manufacturer to meet different markets.
^It also covers some less major Western European languages—as well as some other languages—in full, including Basque, Malay, and the pre-1999 TurkmenLatin alphabet, but this was likely unintended.
^. Go Global Developer Center. Microsoft. Archived from the original on 9 June 2016. Retrieved 22 September 2011.
^ ab"OEM font". Encyclopedia. PCmag.com. from the original on 27 November 2020. Retrieved 19 October 2021.
^Kano, Nadine. "Appendix H Code Pages". Globalization and Localization : Code Page 437 DOS Latin US. Microsoft. from the original on 17 March 2016. Retrieved 14 November 2011.
^ abc"Glossary of Terms Used on this Site". Microsoft. (Please see the description about the term "Alt+Numpad"). Archived from the original on 8 September 2012. Retrieved 17 August 2018.
^Murray Sargent. "Entering Unicode Characters – Murray Sargent: Math in Office". Retrieved 17 August 2018.
^"ALT+NUMPAD ASCII Key Combos: The α and Ω of Creating Obscure Passwords". Retrieved 17 August 2018.
^"Insert ASCII or Unicode Latin-based symbols and characters - Office Support". Microsoft. Retrieved 17 August 2018.
^. Coded character sets and related resources. IBM. 1986 [1984-05-01]. Archived from the original on 9 June 2016. Retrieved 14 November 2011.
^Steele, Shawn (24 April 1996). "cp437_DOSLatinUS to Unicode table" (TXT). 2.00. Unicode Consortium. from the original on 9 June 2016. Retrieved 14 November 2011.
^"cpython/cp437.py at master · python/cpython · GitHub". GitHub. Retrieved 17 August 2018.
^"Greek and Coptic: Range: 0370–03FF" (PDF). The Unicode Standard, Version 9.0. Unicode Consortium. Retrieved 25 February 2017.
^Edwards, Benj (6 November 2015) [2011]. "Origins of the ASCII Smiley Character: An Email Exchange With Dr. David Bradley". from the original on 28 November 2016. Retrieved 27 November 2016. If you look at the first 32 characters in the IBM PC character set you'll see lots of whimsical characters — smiley face, musical notes, playing card suits and others. These were intended for character based games [...] Since we were using 8-bit characters we had 128 new spots to fill. We put serious characters there — three columns of foreign characters, based on our Datamaster experience. Three columns of block graphic characters [...] many customers with Monochrome Display Adapter would have no graphics at all. [...] two columns had math symbols, greek letters (for math) and others [...] about the first 32 characters (x00-x1F)? [...] These characters originated with teletype transmission. But we could display them on the character based screens. So we added a set of "not serious" characters. They were intended as display only characters, not for transmission or storage. Their most probable use would be in character based games. [...] As in most things for the IBM PC, the one year development schedule left little time for contemplation and revision. [...] the character set was developed in a three person 4-hour meeting, and I was one of those on that plane from Seattle to Atlanta. There was some minor revision after that meeting, but there were many other things to design/fix/decide so that was about it. [...] the other participants in that plane trip were Andy Saenz — responsible for the video card, and Lew Eggebrecht — the chief engineer for the PC.
^Wilton, Richard (December 1987). Programmer's Guide to PC & PS/2 Video Systems: Maximum Video Performance Form the EGA, VGA, HGC, and MCGA (1st ed.). Microsoft Press. ISBN1-55615-103-9.
^Joshua D. Neal, Attribute Controller Registers: Attribute Mode Control Register, Hardware Level VGA and SVGA Video Programming Information Page: bit 2 is Line Graphics Enable.
^Mike Jacobs. "MS LineDraw font family - Typography | Microsoft Docs". Microsoft typography. 2.00. Microsoft Corporation. Retrieved 17 August 2018.
^Staff (26 October 2013). "WD97: MS LineDraw Font Not Usable in Word". Microsoft. 2.0. Microsoft. KB179422, Q179422. from the original on 24 March 2016. Retrieved 1 July 2012.
^(PDF). Archived from the original (PDF) on 21 January 2013.
External linksedit
IBM PC memory-mapped video graphics to Unicode on official Unicode site
April 12, 2024
code, page, ccsid, character, original, personal, computer, also, known, cp437, latin, includes, printable, ascii, characters, well, some, accented, letters, diacritics, greek, letters, icons, line, drawing, symbols, sometimes, referred, font, high, ascii, ext. Code page 437 CCSID 437 is the character set of the original IBM PC personal computer 2 It is also known as CP437 OEM US OEM 437 3 PC 8 4 or DOS Latin US 5 The set includes all printable ASCII characters as well as some accented letters diacritics Greek letters icons and line drawing symbols It is sometimes referred to as the OEM font or high ASCII or as extended ASCII 4 one of many mutually incompatible ASCII extensions Code page 437Code page 437 as rendered by an IBM PC using standard VGAMIME IANAIBM437Alias es cp437 437 csPC8CodePage437 1 OEM USLanguage s English German SwedishClassificationExtended ASCII OEM code pageExtendsUS ASCIIOther related encoding s Code page 850 CWI 2vteThis character set remains the primary set in the core of any EGA and VGA compatible graphics card As such text shown when a PC reboots before fonts can be loaded and rendered is typically rendered using this character set note 1 Many file formats developed at the time of the IBM PC are based on code page 437 as well Contents 1 Display adapters 2 Alt codes 3 Character set 4 History 5 Internationalization 6 See also 7 Notes 8 References 9 External linksDisplay adapters editThe original IBM PC contained this font as a 9 14 pixels per character font stored in the ROM of the IBM Monochrome Display Adapter MDA and an 8 8 pixels per character font of the Color Graphics Adapter CGA cards citation needed The IBM Enhanced Graphics Adapter EGA contained an 8 14 pixels per character version and the VGA contained a 9 16 version citation needed All these display adapters have text modes in which each character cell contains an 8 bit character code point see details giving 256 possible values for graphic characters All 256 codes were assigned a graphical character in ROM including the codes from 0 to 31 that were reserved in ASCII for non graphical control characters Various Eastern European PCs used different character sets sometimes user selectable via jumpers or CMOS setup These sets were designed to match 437 as much as possible for instance sharing the code points for many of the line drawing characters while still allowing text in a local language to be displayed Alt codes editA legacy of code page 437 is the number combinations used in Windows Alt codes 6 7 8 A DOS user could enter a character by holding down the Alt key and entering the character code on the numpad 6 and many users memorized the numbers needed for CP437 or for the similar CP850 Although Microsoft Windows used different character sets such as CP1252 the original numbers were emulated so users could continue to use them Microsoft added the ability to type a code from the Windows character set by typing 0 before the digits 6 9 Character set editThe following tables show code page 437 Each character is shown with its equivalent Unicode code point when it is not equal to the character s code A tooltip generally available only when one points to the immediate left of the character shows the Unicode code point name and the decimal Alt code See also the notes below as there are multiple equivalent Unicode characters for some code points Although the ROM provides a graphic for all 256 different possible 8 bit codes some APIs will not print some code points in particular the range 0 31 and the code at 127 10 Instead they will interpret them as control characters For instance many methods of outputting text on the original IBM PC would interpret hex codes 07 08 0A and 0D as BEL BS CR and LF respectively Many printers were also unable to print these characters Code page 437 11 12 13 14 0 1 2 3 4 5 6 7 8 9 A B C D E F0x0 NUL a 263A 263B 2665 2666 2663 2660 2022 25D8 25CB 25D9 2642 2640 266A b 266B 263C1x16 25BA 25C4 2195 203C 00B6 00A7 25AC 21A8 2191 2193 2192 2190 221F 2194 25B2 25BC2x32 SP amp 3x48 0 1 2 3 4 5 6 7 8 9 lt gt 4x64 A B C D E F G H I J K L M N O5x80 P Q R S T U V W X Y Z 6x96 a b c d e f g h i j k l m n o7x112 p q r s t u v w x y z c d 23028x128 C00C7 u00FC e00E9 a00E2 a00E4 a00E0 a00E5 c00E7 e00EA e00EB e00E8 i00EF i00EE i00EC A00C4 A00C59x144 E00C9 ae00E6 AE00C6 o00F4 o00F6 o00F2 u00FB u00F9 y00FF O00D6 U00DC 00A2 00A3 00A5 20A7 ƒ0192Ax160 a00E1 i00ED o00F3 u00FA n00F1 N00D1 ª00AA º00BA 00BF 2310 00AC 00BD 00BC 00A1 00AB 00BBBx176 2591 2592 2593 e 2502 2524 2561 2562 2556 2555 2563 2551 2557 255D 255C 255B 2510Cx192 2514 2534 252C 251C 2500 253C 255E 255F 255A 2554 2569 2566 2560 2550 256C 2567Dx208 2568 2564 2565 2559 2558 2552 2553 256B 256A 2518 250C 2588 2584 258C 2590 2580Ex224 a03B1 ss f 00DF G0393 p g 03C0 S h 03A3 s03C3 µ i 00B5 t03C4 F03A6 8 j 0398 W k 03A9 d l 03B4 221E f m 03C6 e n 03B5 2229Fx240 2261 00B1 2265 2264 o 2320 2321 00F7 2248 00B0 p 2219 00B7 q 221A ⁿ207F 00B2 25A0 NBSP r 00A0 Symbols and punctuation When translating to Unicode some codes do not have a unique single Unicode equivalent the correct choice may depend upon context 0 draws a blank space but usage as the C string terminator means it is more accurately translated as NUL Mapping as shown to the beamed quavers U 266B follows data provided by the Unicode Consortium 15 In IBM s GCGID Graphic Character Global IDentifier system of character IDs this is SM910000 simply annotated as Two Musical Notes 12 13 however the reference glyph shows two beamed semiquavers U 266C 12 In the specification for IBM Japanese Host code SM910080 i e SM910000 with the fullwidth attribute set is explicitly mapped to U 266C and accordingly shows two semiquavers 16 124 7Chex The actual glyph at this position is a broken bar U 00A6 in the original IBM PC and compatibles font as rendered by the original MDA This rendering was later adopted for CGA EGA and VGA see image at the beginning of the article However almost all software assumes this code is the ASCII character U 007C for example programming languages use it as or In the early 1990s it was clarified by whom that there is vertical bar in ASCII at this position and that the broken bar symbol is not part of ASCII 127 7Fhex is a house but was also sometimes used as Greek capital delta U 0394 D Could also serve as an integral extension U 23AE in IBM s font nbsp Comparison of characters in the E0 to EF range across various IBM products 225 E1hex is identified by IBM as Latin Sharp s Small 13 U 00DF ss but is sometimes rendered in OEM fonts as Greek small beta U 03B2 b The placement of this Latin character among Greek characters suggests intended multi use 227 E3hex is identified by IBM as Greek Pi Small U 03C0 p but is sometimes rendered in OEM fonts as Greek capital pi U 03A0 P or the n ary product sign U 220F 228 E4hex is identified by IBM as Greek Sigma Capital U 03A3 S but is also used as the n ary summation sign U 2211 230 E6hex is identified by IBM as Greek Mu Small U 03BC m but is also used as the micro sign U 00B5 µ In Unicode IBM s Greek GCGID table 17 maps the character in this code page to the Greek letter but Python for example maps it to the micro sign 233 E9hex is identified by IBM as Greek Theta Capital U 0398 8 12 13 However these symbols are for mathematics and physics in which lowercase theta is much more commonly used e g for polar coordinates 234 EAhex is identified by IBM as Greek Omega Capital U 03A9 W but is also used as the ohm sign U 2126 W Unicode considers the characters to be equivalent and suggests that U 03A9 be used in both contexts 18 235 EBhex is identified by IBM as Greek Delta Small U 03B4 d It was also unofficially used for the small eth U 00F0 d and the partial derivative sign U 2202 237 EDhex is identified by IBM as Greek Phi Small Closed Form U 03D5 ϕ or from the italicized math set U 1D719 𝜙 but in some codecs e g the codec library of Python 19 is mapped to Unicode as the open or loopy form U 03C6 f Comparison of IBM s Greek GCGID table 17 with Unicode s Greek code chart 20 shows where IBM for example reversed the open and closed forms when mapping to Unicode This character is also used as the empty set sign U 2205 the diameter sign U 2300 and the Latin letter O with stroke U 00D8 O and U 00F8 o 238 EEhex is identified by IBM as Greek Epsilon Small U 03B5 e but is sometimes rendered in OEM fonts as the element of sign U 2208 It was often used as the euro sign U 20AC 244 F4hex and 245 F5hex are the upper and lower portion of the integral symbol and they can be extended with the character 179 B3hex the vertical line of the box drawing block 244 could also be used for the long s character U 017F ſ 249 F9hex and 250 FAhex are almost indistinguishable the first is a slightly larger dot than the second both were used as bullets middle dot and multiplication dot U 2219 251 FBhex was also sometimes used as a check mark U 2713 255 FFhex draws a blank space the use as non breaking space NBSP has precedent in word processors designed for the IBM PC History editThe repertoire of code page 437 was taken from the character set of Wang word processing machines according to Bill Gates in an interview with Gates and Paul Allen that appeared in the 2 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 According to an interview with David J Bradley developer of the PC s ROM BIOS the characters were decided upon during a four hour meeting on a plane trip from Seattle to Atlanta by Andy Saenz responsible for the video card Lew Eggebrecht chief engineer for the PC and himself 21 The selection of graphic characters has some internal logic Table rows 0 and 1 codes 0 to 31 00hex to 1Fhex are assorted dingbats complementary and decorative characters The isolated character 127 7Fhex also belongs to this group Table rows 2 to 7 codes 32 to 126 20hex to 7Ehex are the standard ASCII printable characters Table rows 8 to 10 codes 128 to 175 80hex to AFhex are a selection of international text characters Table rows 11 to 13 codes 176 to 223 B0hex to DFhex are box drawing and block characters This block is arranged so that characters 192 to 223 C0hex to DFhex contain all the right arms and right filled areas The original IBM PC MDA display adapter stored the code page 437 character glyphs as bitmaps eight pixels wide but for visual enhancement displayed them every nine pixels on screen This range of characters had the eighth pixel column duplicated by special hardware circuitry 22 thus filling in gaps in lines and filled areas The VGA adapter allows this behaviour to be turned on or off 23 Table rows 14 and 15 codes 224 to 254 E0hex to FEhex are devoted to mathematical symbols where the first twelve are a selection of Greek letters commonly used in physics Most fonts for Microsoft Windows include the special graphic characters at the Unicode indexes shown as they are part of the WGL4 set that Microsoft encourages font designers to support The monospaced raster font family Terminal was an early font that replicated all code page 437 characters at least at some resolutions To draw these characters directly from these code points a Microsoft Windows font called MS Linedraw 24 replicates all of the code page 437 characters thus providing one way to display DOS text on a modern Windows machine as it was shown in DOS with limitations 25 Code page 1055 also known as HP symbol set 0L 26 is a subset which includes the box drawing half blocks black circles the black circle replaces the bullet which replaces the middle dot in this code page and black square and moves them to the upper half the space is also included 27 Internationalization editCode page 437 has a series of international characters mainly values 128 to 175 80hex to AFhex However it only covers a few major Western European languages in full including English German and Swedish note 2 and so lacks several characters mostly capital letters important to many major Western European languages Spanish A I o and U French A A E E E I I O Œ œ U U and Ÿ Portuguese A A A A a E I o O O o and U Catalan A E I I O o and U Italian A E I O and U Icelandic A D d I o U Y y TH and th Danish Norwegian O and o Character number 237 EDhex the small phi closed form could be used as a surrogate even though it may not render well furthermore it tends to map to Unicode and or render in Unicode fonts as the open form phi or the closed vertical form phi which are even further from the O with stroke To compensate the Danish Norwegian and Icelandic code pages 865 and 861 replaced cent sign with o and the yen sign with O Most Greek alphabet symbols were omitted beyond the basic math symbols They were included in the Greek language code pages 737 and 869 Some of the Greek symbols that were already in code page 437 had their glyphs changed from mathematical or scientific forms to match the actual use in Greek Along with the cent pound sterling and yen yuan currency symbols it has a couple of former European currency symbols the florin ƒ Netherlands and the peseta Spain The presence of the last is unusual since the Spanish peseta was never an internationally relevant currency and also never had a symbol of its own it was simply abbreviated as Pt Pta Pts or Ptas Spanish models of the IBM electric typewriter however also had a single position devoted to it Later DOS character sets such as code page 850 DOS Latin 1 code page 852 DOS Central European and code page 737 DOS Greek filled the gaps for international use with some compatibility with code page 437 by retaining the single and double box drawing characters while discarding the mixed ones e g horizontal double vertical single All code page 437 characters have similar glyphs in Unicode and in Microsoft s WGL4 character set and therefore are available in most fonts in Microsoft Windows and also in the default VGA font of the Linux kernel and the ISO 10646 fonts for X11 See also editAlt code ANSI ASCII Semigraphical characters Atari ST character set derived from code page 437Notes edit Systems available in Eastern European Arabic and Asian countries often use a different set however these sets are designed to match 437 as much as possible The designation OEM for original equipment manufacturer indicates that the set could be changed by the manufacturer to meet different markets It also covers some less major Western European languages as well as some other languages in full including Basque Malay and the pre 1999 Turkmen Latin alphabet but this was likely unintended References edit Character Sets Internet Assigned Numbers Authority IANA 12 December 2018 CCSID 437 information document Archived from the original on 27 March 2016 OEM 437 Go Global Developer Center Microsoft Archived from the original on 9 June 2016 Retrieved 22 September 2011 a b OEM font Encyclopedia PCmag com Archived from the original on 27 November 2020 Retrieved 19 October 2021 Kano Nadine Appendix H Code Pages Globalization and Localization Code Page 437 DOS Latin US Microsoft Archived from the original on 17 March 2016 Retrieved 14 November 2011 a b c Glossary of Terms Used on this Site Microsoft Please see the description about the term Alt Numpad Archived from the original on 8 September 2012 Retrieved 17 August 2018 Murray Sargent Entering Unicode Characters Murray Sargent Math in Office Retrieved 17 August 2018 ALT NUMPAD ASCII Key Combos The a and W of Creating Obscure Passwords Retrieved 17 August 2018 Insert ASCII or Unicode Latin based symbols and characters Office Support Microsoft Retrieved 17 August 2018 SBCS code page information document CPGID 00437 Coded character sets and related resources IBM 1986 1984 05 01 Archived from the original on 9 June 2016 Retrieved 14 November 2011 Steele Shawn 24 April 1996 cp437 DOSLatinUS to Unicode table TXT 2 00 Unicode Consortium Archived from the original on 9 June 2016 Retrieved 14 November 2011 a b c d Code Page CPGID 00437 PDF IBM a b c d Code Page CPGID 00437 Coded character sets and related resources IBM 1984 Retrieved 3 August 2023 International Components for Unicode ICU ibm 437 P100 1995 ucm 3 December 2002 Whistler Ken 27 July 1999 IBM PC memory mapped video graphics to Unicode Unicode Consortium IBM Japanese Graphic Character Set Kanji DBCS Host and DBCS PC PDF IBM 2002 C H 3 3220 024 2002 11 a b Graphic character identifiers Alphabetics Greek Coded character sets and related resources IBM Retrieved 25 February 2017 The Unicode Consortium 21 May 2003 Chapter 7 European Alphabetic Scripts The Unicode Standard 4 0 PDF Addison Wesley published August 2003 p 176 ISBN 0 321 18578 1 Retrieved 9 June 2016 cpython cp437 py at master python cpython GitHub GitHub Retrieved 17 August 2018 Greek and Coptic Range 0370 03FF PDF The Unicode Standard Version 9 0 Unicode Consortium Retrieved 25 February 2017 Edwards Benj 6 November 2015 2011 Origins of the ASCII Smiley Character An Email Exchange With Dr David Bradley Archived from the original on 28 November 2016 Retrieved 27 November 2016 If you look at the first 32 characters in the IBM PC character set you ll see lots of whimsical characters smiley face musical notes playing card suits and others These were intended for character based games Since we were using 8 bit characters we had 128 new spots to fill We put serious characters there three columns of foreign characters based on our Datamaster experience Three columns of block graphic characters many customers with Monochrome Display Adapter would have no graphics at all two columns had math symbols greek letters for math and others about the first 32 characters x00 x1F These characters originated with teletype transmission But we could display them on the character based screens So we added a set of not serious characters They were intended as display only characters not for transmission or storage Their most probable use would be in character based games As in most things for the IBM PC the one year development schedule left little time for contemplation and revision the character set was developed in a three person 4 hour meeting and I was one of those on that plane from Seattle to Atlanta There was some minor revision after that meeting but there were many other things to design fix decide so that was about it the other participants in that plane trip were Andy Saenz responsible for the video card and Lew Eggebrecht the chief engineer for the PC Wilton Richard December 1987 Programmer s Guide to PC amp PS 2 Video Systems Maximum Video Performance Form the EGA VGA HGC and MCGA 1st ed Microsoft Press ISBN 1 55615 103 9 Joshua D Neal Attribute Controller Registers Attribute Mode Control Register Hardware Level VGA and SVGA Video Programming Information Page bit 2 is Line Graphics Enable Mike Jacobs MS LineDraw font family Typography Microsoft Docs Microsoft typography 2 00 Microsoft Corporation Retrieved 17 August 2018 Staff 26 October 2013 WD97 MS LineDraw Font Not Usable in Word Microsoft 2 0 Microsoft KB179422 Q179422 Archived from the original on 24 March 2016 Retrieved 1 July 2012 HP Symbol sets Code Page 1055 PDF Archived from the original PDF on 21 January 2013 External links editIBM PC memory mapped video graphics to Unicode on official Unicode site Retrieved from https en wikipedia org w index php title Code page 437 amp oldid 1215076037, wikipedia, wiki, book, books, library,
