View source for VISCII

{{short description|Unofficial character encoding for the Vietnamese alphabet}}
{{Distinguish|text=[[VSCII]] (Vietnamese Standard Code for Information Interchange), a family of official encodings for Vietnamese}}
{{Infobox character encoding
|name = VISCII
|mime = VISCII
|alias = 
|by = Viet-Std Group
|definitions = {{IETF RFC|1456}}
|lang = [[Vietnamese language|Vietnamese]], [[English language|English]]
|basedon = [[ASCII]]
|classification = 8-bit [[SBCS]]
}}

'''VISCII''' is an unofficially-defined modified [[ASCII]] [[character encoding]] for [[Vietnamese language and computers|using the Vietnamese language with computers]].  It should not be confused with the similarly-named officially registered [[VSCII]] encoding. VISCII keeps the 95 printable characters of ASCII unmodified, but it replaces 6 of the 33 control characters with printable characters. It adds 128 [[precomposed character]]s. [[Unicode]] and the [[Windows-1258]] code page are now used for virtually all Vietnamese computer data,{{cn|date=July 2020}} but legacy VSCII and VISCII files may need conversion.

==History and naming==
VISCII was designed by the Vietnamese Standardization Working Group (Viet-Std Group)<ref>{{cite web |url=http://vietstd.sourceforge.net/ |title=Vietnamese-Standard Working Group Home Page |access-date=2019-08-23 |publisher=Viet-Std Group |first1=Quang |last1=Phung |first2=Hoc D. |last2=Ngo |first3=Cuong |last3=Bui}}</ref> led by Christopher Cuong T. Nguyen, Cuong M. Bui, and Hoc D. Ngo based in [[Silicon Valley]], California in 1992 while they were working with the Unicode consortium to include pre-composed Vietnamese characters in the Unicode standard. VISCII, along with [[Vietnamese Quoted-Readable|VIQR]], was first published in a bilingual report in September 1992, in which it was dubbed the "Vietnamese Standard Code for Information Interchange".<ref name="rep92">{{cite tech report |url=http://vietstd.sourceforge.net/report/rep92.htm |title=Vietnamese Character Encoding Standardization Report - VISCII And VIQR 1.1 Character Encoding Specifications |date=1992 |publisher=Viet-Std Group}}</ref> The report noted a proliferation in computer usage in Vietnam and the increasing volume of computer-based communications among Vietnamese abroad, that existing applications used vendor-specific encodings which were unable to interoperate with one another, and that [[De facto standard|standardisation]] between vendors was therefore necessary. The successful inclusion of composed and precomposed Vietnamese in Unicode 1.0 was the result of the lessons learned from the development of 8-bit VISCII and 7-bit VIQR.<ref name="rep92" />

The next year, in 1993, Vietnam adopted [[TCVN 5712]], its first national standard in the [[information technology]] domain.<ref name="leipzig">{{cite web |url=http://www.informatik.uni-leipzig.de/~duc/software/misc/tcvn.txt |archive-url=https://web.archive.org/web/20170111042331/http://www.informatik.uni-leipzig.de/~duc/software/misc/tcvn.txt |archive-date=2017-01-11 |title=[news] TCVN 5712:1993 (VSCII) -- Vietnamese national standard |date=1993-06-02}}</ref> This defined a character encoding named [[VSCII]], which had been developed by the [[Vietnam Standard|TCVN]] Technical Committee on Information Technology (TCVN/TC1), and with its name standing for "Vietnamese Standard Code for Information Interchange".<ref name="leipzig" /> VSCII is incompatible with, and otherwise unrelated to, the earlier-published VISCII.<ref>{{cite book |section=Chapter 1: CJKV Information Processing Overview (§ Are VISCII and VSCII identical? What about TCVN?) |page=17 |title=CJKV Information Processing |edition=2nd |last=Lunde |first=Ken |date=13 January 2009 |isbn=978-0-596-51447-1}}</ref> Unlike VISCII, VSCII is a "Vietnamese Standard" in the sense of a [[Standards organization#National standards bodies|national standard]].

VISCII and [[VIQR]] were approved as the informational-status {{IETF RFC|1456}}, attributed to the Viet-Std group and dated May 1993. As is the case with IETF RFCs, <nowiki>RFC 1456</nowiki> notes them to be "conventions" used by overseas Vietnamese speakers on [[Usenet]], and that it "specifies no level of standard". In spite of this, it continues to call VISCII the "VIetnamese Standard Code for Information Interchange" (the same name taken by VSCII).<ref>{{cite IETF |title=Conventions for Encoding the Vietnamese Language |rfc=1456 |author=Vietnamese Standardization Working Group |date=May 1993 |publisher=[[Internet Engineering Task Force|IETF]]}}</ref> The labels <code>VISCII</code> and <code>csVISCII</code> are registered with the [[IANA]] for VISCII, with reference to <nowiki>RFC 1456</nowiki>.<ref name="iana">{{cite web|title=Character Sets|url=https://www.iana.org/assignments/character-sets/character-sets.xhtml|publisher=[[IANA]]}}</ref> (There is, on the other hand, no official IANA label for TCVN 5712 / VSCII, although <code>x-viet-tcvn5712</code> was previously supported by [[Mozilla Firefox]].<ref>{{cite web |url=https://groups.google.com/d/msg/mozilla.dev.apps.thunderbird/2P5kCJJS_WI/oWhT0STivL0J |last=Sivonen |first=Henri |title=Character encoding changes in m-c require c-c action |work=mozilla.dev.apps.thunderbird |date=2014-09-26}}</ref>)

==Design==
A traditional [[extended ASCII]] character set consists of the ASCII set plus up to 128 characters. Vietnamese requires 134 additional letter-diacritic combinations, which is six too many. There are (short of dropping tone mark support for capital letters, as in [[VSCII#VSCII-3|VSCII-3]]) essentially four different ways to handle this problem:
#Use [[variable-width encoding]] (as does [[UTF-8]])
#Include [[combining character|combining diacritical marks]] for tone marks (as do [[VSCII#VSCII-2|VSCII-2]] and [[Windows-1258]]) or for diacritics in general (as do [[ANSEL]] and [[VNI#VNI Encoding (Windows/Unix)|VNI]])
#Replace some ASCII punctuation, preferably punctuation which is not invariant in [[ISO 646]] (as does [[VNI#VNI Encoding for DOS|VNI for DOS]])
#Replace at least six of the basic ASCII [[control character]]s (as do [[VPS character encoding|VPS]] and [[VSCII#VSCII-1|VSCII-1]])

VISCII went for the last option, replacing six of the least problematic (e.g., least likely to be recognised by an application and acted on specially) [[C0 and C1 control codes|C0 control codes]] (STX, ENQ, ACK, DC4, EM, and RS) with six of the least-used uppercase letter-diacritic combinations.<ref name="rep92" /> While this option may cause programs that use those control codes to malfunction when handling VISCII text, it creates fewer complications than the other two options (the designers note that non-[[8-bit clean]] transmission had been found to pose more difficulty in practice than the control character re-use).<ref name="rep92" /> Nonetheless, locations of both C0 or C1 control characters and the codes used for the [[non-breaking space]] in [[ISO-8859-1]], [[Mac OS Roman]] and [[OEM-US]] were deliberately assigned to uppercase letters, with the intention of making use of lowercase codepoints with an all-capital font a serviceable workaround if graphical characters could not be displayed for those codes.<ref name="rep92" />

However, using up all the extended [[code point]]s for accented letters left no room to add useful symbols, superscripted numbers, curved quotes, proper dashes, etc., like most other extended ASCII character sets.

Location of characters deliberately mostly follows [[ISO-8859-1]] where there are characters in common between the two code pages (the uppercase [[Õ]] being noted as an exception), motivated by user friendliness concerns.<ref name="rep92" />

==Support==
VISCII is partially supported by the [http://trichlor.sf.net/ TriChlor Software Group] in California, which has released various  VISCII-compliant software packages, libraries, and fonts for MS-DOS and Windows, Unix, and Macintosh. VISCII-compliant software is available at many [https://web.archive.org/web/20201125073651/http://ftp.monash.edu.au/pub/vietnam/ FTP sites].

VISCII was historically offered as an encoding for outgoing [[email]] by [[Mozilla Thunderbird]].<ref>{{cite web |url=https://groups.google.com/d/msg/mozilla.dev.apps.thunderbird/2P5kCJJS_WI/oWhT0STivL0J |last=Sivonen |first=Henri |title=Character encoding changes in m-c require c-c action |work=mozilla.dev.apps.thunderbird |date=2014-09-26 |quotation=VISCII and armscii-8 are special in the sense that, for long time, Thunderbird itself (misguidedly) provided these encodings in the user interface for the choice of outgoing character encoding when composing a message. Therefore, it is possible that there exists a Thunderbird-created legacy of VISCII and armscii-8 email and Usenet posts.}}</ref> It was also supported by the Windows Vietnamese keyboard software, WinVNKey, created by Christopher Cuong T. Nguyen and later upgraded through various Windows versions by Hoc D. Ngo and others.

VISCII was mostly used by overseas Vietnamese speakers, with [[VSCII]] (TCVN) being more popular in northern Vietnam and [[VNI#VNI Encoding|VNI]] being more popular in southern Vietnam.<ref>{{cite web |url=http://winvnkey.sourceforge.net/some-special-functions-of-winvnkey.htm#Why_having_Vietnamese_charset_conversion |title=5. Why Having Vietnamese Charset (Character Set – Encoding) Conversion? |work=Some special functions of WinVNKey |first1=Hoc Dinh |last1=Ngo |first2=TuBinh |last2=Tran}}</ref>

==Character set==

{|{{chset-table-header1|VISCII}}
|-
|{{chset-left1|0x}}
|{{chset-ctrl1|U+0000 NULL|[[Null character|NUL]]}}
|{{chset-ctrl1|U+0001 START OF HEADING|[[Start of heading|SOH]]}}
|{{chset-cell1|u=1EB2|U+1EB2 LATIN CAPITAL LETTER A WITH BREVE AND HOOK ABOVE|[[Ẳ]]|style=background:#FFD}}
|{{chset-ctrl1|U+0003 END OF TEXT|[[End of text|ETX]]}}
|{{chset-ctrl1|U+0004 END OF TRANSMISSION|[[End of transmission character|EOT]]}}
|{{chset-cell1|u=1EB4|U+1EB4 LATIN CAPITAL LETTER A WITH BREVE AND TILDE|[[Ẵ]]|style=background:#FFD}}
|{{chset-cell1|u=1EAA|U+1EAA LATIN CAPITAL LETTER A WITH CIRCUMFLEX AND TILDE|[[Ẫ]]|style=background:#FFD}}
|{{chset-ctrl1|U+0007 BELL|[[Bell character|BEL]]}}
|{{chset-ctrl1|U+0008 BACKSPACE|[[Backspace|BS]]}}
|{{chset-ctrl1|U+0009 CHARACTER TABULATION|[[Horizontal tab|HT]]}}
|{{chset-ctrl1|U+000A LINE FEED (LF)|[[Line feed|LF]]}}
|{{chset-ctrl1|U+000B LINE TABULATION|[[Vertical tab|VT]]}}
|{{chset-ctrl1|U+000C FORM FEED (FF)|[[Form feed|FF]]}}
|{{chset-ctrl1|U+000D CARRIAGE RETURN (CR)|[[Carriage return|CR]]}}
|{{chset-ctrl1|U+000E SHIFT OUT|[[Shift out|SO]]}}
|{{chset-ctrl1|U+000F SHIFT IN|[[Shift in|SI]]}}
|-
|{{chset-left1|1x}}
|{{chset-ctrl1|U+0010 DATA LINK ESCAPE|[[Data link escape|DLE]]}}
|{{chset-ctrl1|U+0011 DEVICE CONTROL ONE|[[Device Control 1|DC1]]}}
|{{chset-ctrl1|U+0012 DEVICE CONTROL TWO|[[Device Control 2|DC2]]}}
|{{chset-ctrl1|U+0013 DEVICE CONTROL THREE|[[Device Control 3|DC3]]}}
|{{chset-cell1|u=1EF6|U+1EF6 LATIN CAPITAL LETTER Y WITH HOOK ABOVE|[[Ỷ]]|style=background:#FFD}}
|{{chset-ctrl1|U+0015 NEGATIVE ACKNOWLEDGE|[[Negative acknowledge character|NAK]]}}
|{{chset-ctrl1|U+0016 SYNCHRONOUS IDLE|[[Synchronous idle|SYN]]}}
|{{chset-ctrl1|U+0017 END OF TRANSMISSION BLOCK|[[End of transmission block|ETB]]}}
|{{chset-ctrl1|U+0018 CANCEL|[[Cancel character|CAN]]}}
|{{chset-cell1|u=1EF8|U+1EF8 LATIN CAPITAL LETTER Y WITH TILDE|[[Ỹ]]|style=background:#FFD}}
|{{chset-ctrl1|U+001A SUBSTITUTE|[[Substitute character|SUB]]}}
|{{chset-ctrl1|U+001B ESCAPE|[[Escape character|ESC]]}}
|{{chset-ctrl1|U+001C INFORMATION SEPARATOR FOUR|[[File separator|FS]]}}
|{{chset-ctrl1|U+001D INFORMATION SEPARATOR THREE|[[Group separator|GS]]}}
|{{chset-cell1|u=1EF4|U+1EF4 LATIN CAPITAL LETTER Y WITH DOT BELOW|[[Ỵ]]|style=background:#FFD}}
|{{chset-ctrl1|U+001F INFORMATION SEPARATOR ONE|[[Unit separator|US]]}}
|-
|{{chset-left1|2x}}
|{{chset-ctrl1|U+0020|&nbsp;[[space character|SP]]&nbsp;}}
|{{chset-cell1|U+0021 EXCLAMATION MARK|[[Exclamation mark|!]]}}
|{{chset-cell1|U+0022 QUOTATION MARK|[[Quotation mark|"]]}}
|{{chset-cell1|U+0023 NUMBER SIGN|[[Number sign|#]]}}
|{{chset-cell1|U+0024 DOLLAR SIGN|[[Dollar sign|$]]}}
|{{chset-cell1|U+0025 PERCENT SIGN|[[Percent sign|%]]}}
|{{chset-cell1|U+0026 AMPERSAND|[[Ampersand|&amp;]]}}
|{{chset-cell1|U+0027 APOSTROPHE|[[Apostrophe|']]}}
|{{chset-cell1|U+0028 LEFT PARENTHESIS|[[Bracket|(]]}}
|{{chset-cell1|U+0029 RIGHT PARENTHESIS|[[Bracket|)]]}}
|{{chset-cell1|U+002A ASTERISK|[[Asterisk|*]]}}
|{{chset-cell1|U+002B PLUS SIGN|[[Plus and minus signs|+]]}}
|{{chset-cell1|U+002C COMMA|[[Comma (punctuation)|,]]}}
|{{chset-cell1|U+002D HYPHEN-MINUS|[[Plus and minus signs|-]]}}
|{{chset-cell1|U+002E FULL STOP|[[Full stop|.]]}}
|{{chset-cell1|U+002F SOLIDUS|[[Slash (punctuation)|/]]}}
|-
|{{chset-left1|3x}}
|{{chset-cell1|U+0030 DIGIT ZERO|[[0 (number)|0]]}}
|{{chset-cell1|U+0031 DIGIT ONE|[[1 (number)|1]]}}
|{{chset-cell1|U+0032 DIGIT TWO|[[2 (number)|2]]}}
|{{chset-cell1|U+0033 DIGIT THREE|[[3 (number)|3]]}}
|{{chset-cell1|U+0034 DIGIT FOUR|[[4 (number)|4]]}}
|{{chset-cell1|U+0035 DIGIT FIVE|[[5 (number)|5]]}}
|{{chset-cell1|U+0036 DIGIT SIX|[[6 (number)|6]]}}
|{{chset-cell1|U+0037 DIGIT SEVEN|[[7 (number)|7]]}}
|{{chset-cell1|U+0038 DIGIT EIGHT|[[8 (number)|8]]}}
|{{chset-cell1|U+0039 DIGIT NINE|[[9 (number)|9]]}}
|{{chset-cell1|U+003A COLON|[[colon (punctuation)|&#x3A;]]}}
|{{chset-cell1|U+003B SEMICOLON|[[semicolon|&#x3B;]]}}
|{{chset-cell1|U+003C LESS-THAN SIGN|[[angle bracket|&lt;]]}}
|{{chset-cell1|U+003D EQUALS SIGN|[[equal sign|{{=}}]]}}
|{{chset-cell1|U+003E GREATER-THAN SIGN|[[angle bracket|&gt;]]}}
|{{chset-cell1|U+003F QUESTION MARK|[[question mark|?]]}}
|-
|{{chset-left1|4x}}
|{{chset-cell1|U+0040 COMMERCIAL AT|[[@]]}}
|{{chset-cell1|U+0041 LATIN CAPITAL LETTER A|[[A]]}}
|{{chset-cell1|U+0042 LATIN CAPITAL LETTER B|[[B]]}}
|{{chset-cell1|U+0043 LATIN CAPITAL LETTER C|[[C]]}}
|{{chset-cell1|U+0044 LATIN CAPITAL LETTER D|[[D]]}}
|{{chset-cell1|U+0045 LATIN CAPITAL LETTER E|[[E]]}}
|{{chset-cell1|U+0046 LATIN CAPITAL LETTER F|[[F]]}}
|{{chset-cell1|U+0047 LATIN CAPITAL LETTER G|[[G]]}}
|{{chset-cell1|U+0048 LATIN CAPITAL LETTER H|[[H]]}}
|{{chset-cell1|U+0049 LATIN CAPITAL LETTER I|[[I]]}}
|{{chset-cell1|U+004A LATIN CAPITAL LETTER J|[[J]]}}
|{{chset-cell1|U+004B LATIN CAPITAL LETTER K|[[K]]}}
|{{chset-cell1|U+004C LATIN CAPITAL LETTER L|[[L]]}}
|{{chset-cell1|U+004D LATIN CAPITAL LETTER M|[[M]]}}
|{{chset-cell1|U+004E LATIN CAPITAL LETTER N|[[N]]}}
|{{chset-cell1|U+004F LATIN CAPITAL LETTER O|[[O]]}}
|-
|{{chset-left1|5x}}
|{{chset-cell1|U+0050 LATIN CAPITAL LETTER P|[[P]]}}
|{{chset-cell1|U+0051 LATIN CAPITAL LETTER Q|[[Q]]}}
|{{chset-cell1|U+0052 LATIN CAPITAL LETTER R|[[R]]}}
|{{chset-cell1|U+0053 LATIN CAPITAL LETTER S|[[S]]}}
|{{chset-cell1|U+0054 LATIN CAPITAL LETTER T|[[T]]}}
|{{chset-cell1|U+0055 LATIN CAPITAL LETTER U|[[U]]}}
|{{chset-cell1|U+0056 LATIN CAPITAL LETTER V|[[V]]}}
|{{chset-cell1|U+0057 LATIN CAPITAL LETTER W|[[W]]}}
|{{chset-cell1|U+0058 LATIN CAPITAL LETTER X|[[X]]}}
|{{chset-cell1|U+0059 LATIN CAPITAL LETTER Y|[[Y]]}}
|{{chset-cell1|U+005A LATIN CAPITAL LETTER Z|[[Z]]}}
|{{chset-cell1|U+005B LEFT SQUARE BRACKET|[[square brackets|&#91;]]}}
|{{chset-cell1|U+005C REVERSE SOLIDUS|[[backslash|\]]}}
|{{chset-cell1|U+005D RIGHT SQUARE BRACKET|[[square brackets|&#93;]]}}
|{{chset-cell1|U+005E CIRCUMFLEX ACCENT|[[circumflex|^]]}}
|{{chset-cell1|U+005F LOW LINE|[[underscore|_]]}}
|-
|{{chset-left1|6x}}
|{{chset-cell1|U+0060 GRAVE ACCENT|[[`]]}}
|{{chset-cell1|U+0061 LATIN SMALL LETTER A|[[a]]}}
|{{chset-cell1|U+0062 LATIN SMALL LETTER B|[[b]]}}
|{{chset-cell1|U+0063 LATIN SMALL LETTER C|[[c]]}}
|{{chset-cell1|U+0064 LATIN SMALL LETTER D|[[d]]}}
|{{chset-cell1|U+0065 LATIN SMALL LETTER E|[[e]]}}
|{{chset-cell1|U+0066 LATIN SMALL LETTER F|[[f]]}}
|{{chset-cell1|U+0067 LATIN SMALL LETTER G|[[g]]}}
|{{chset-cell1|U+0068 LATIN SMALL LETTER H|[[h]]}}
|{{chset-cell1|U+0069 LATIN SMALL LETTER I|[[i]]}}
|{{chset-cell1|U+006A LATIN SMALL LETTER J|[[j]]}}
|{{chset-cell1|U+006B LATIN SMALL LETTER K|[[k]]}}
|{{chset-cell1|U+006C LATIN SMALL LETTER L|[[l]]}}
|{{chset-cell1|U+006D LATIN SMALL LETTER M|[[m]]}}
|{{chset-cell1|U+006E LATIN SMALL LETTER N|[[n]]}}
|{{chset-cell1|U+006F LATIN SMALL LETTER O|[[o]]}}
|-
|{{chset-left1|7x}}
|{{chset-cell1|U+0070 LATIN SMALL LETTER P|[[p]]}}
|{{chset-cell1|U+0071 LATIN SMALL LETTER Q|[[q]]}}
|{{chset-cell1|U+0072 LATIN SMALL LETTER R|[[r]]}}
|{{chset-cell1|U+0073 LATIN SMALL LETTER S|[[s]]}}
|{{chset-cell1|U+0074 LATIN SMALL LETTER T|[[t]]}}
|{{chset-cell1|U+0075 LATIN SMALL LETTER U|[[u]]}}
|{{chset-cell1|U+0076 LATIN SMALL LETTER V|[[v]]}}
|{{chset-cell1|U+0077 LATIN SMALL LETTER W|[[w]]}}
|{{chset-cell1|U+0078 LATIN SMALL LETTER X|[[x]]}}
|{{chset-cell1|U+0079 LATIN SMALL LETTER Y|[[y]]}}
|{{chset-cell1|U+007A LATIN SMALL LETTER Z|[[z]]}}
|{{chset-cell1|U+007B LEFT CURLY BRACKET|[[braces (punctuation)|{]]}}
|{{chset-cell1|U+007C VERTICAL LINE|[[vertical bar|{{pipe}}]]}}
|{{chset-cell1|U+007D RIGHT CURLY BRACKET|[[braces (punctuation)|}]]}}
|{{chset-cell1|U+007E TILDE|[[tilde|~]]}}
|{{chset-ctrl1|U+007F DELETE|[[delete character|DEL]]}}
|-
|{{chset-left1|8x}}
|{{chset-cell1|u=1EA0|U+1EA0 LATIN CAPITAL LETTER A WITH DOT BELOW|[[Ạ]]|style=background:#FFD}}
|{{chset-cell1|u=1EAE|U+1EAE LATIN CAPITAL LETTER A WITH BREVE AND ACUTE|[[Ắ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB0|U+1EB0 LATIN CAPITAL LETTER A WITH BREVE AND GRAVE|[[Ằ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB6|U+1EB6 LATIN CAPITAL LETTER A WITH BREVE AND DOT BELOW|[[Ặ]]|style=background:#FFD}}
|{{chset-cell1|u=1EA4|U+1EA4 LATIN CAPITAL LETTER A WITH CIRCUMFLEX AND ACUTE|[[Ấ]]|style=background:#FFD}}
|{{chset-cell1|u=1EA6|U+1EA6 LATIN CAPITAL LETTER A WITH CIRCUMFLEX AND GRAVE|[[Ầ]]|style=background:#FFD}}
|{{chset-cell1|u=1EA8|U+1EA8 LATIN CAPITAL LETTER A WITH CIRCUMFLEX AND HOOK ABOVE|[[Ẩ]]|style=background:#FFD}}
|{{chset-cell1|u=1EAC|U+1EAC LATIN CAPITAL LETTER A WITH CIRCUMFLEX AND DOT BELOW|[[Ậ]]|style=background:#FFD}}
|{{chset-cell1|u=1EBC|U+1EBC LATIN CAPITAL LETTER E WITH TILDE|[[Ẽ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB8|U+1EB8 LATIN CAPITAL LETTER E WITH DOT BELOW|[[Ẹ]]|style=background:#FFD}}
|{{chset-cell1|u=1EBE|U+1EBE LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND ACUTE|[[Ế]]|style=background:#FFD}}
|{{chset-cell1|u=1EC0|U+1EC0 LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND GRAVE|[[Ề]]|style=background:#FFD}}
|{{chset-cell1|u=1EC2|U+1EC2 LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND HOOK ABOVE|[[Ể]]|style=background:#FFD}}
|{{chset-cell1|u=1EC4|U+1EC4 LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND TILDE|[[Ễ]]|style=background:#FFD}}
|{{chset-cell1|u=1EC6|U+1EC6 LATIN CAPITAL LETTER E WITH CIRCUMFLEX AND DOT BELOW|[[Ệ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED0|U+1ED0 LATIN CAPITAL LETTER O WITH CIRCUMFLEX AND ACUTE|[[Ố]]|style=background:#FFD}}
|-
|{{chset-left1|9x}}
|{{chset-cell1|u=1ED2|U+1ED2 LATIN CAPITAL LETTER O WITH CIRCUMFLEX AND GRAVE|[[Ồ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED4|U+1ED4 LATIN CAPITAL LETTER O WITH CIRCUMFLEX AND HOOK ABOVE|[[Ổ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED6|U+1ED6 LATIN CAPITAL LETTER O WITH CIRCUMFLEX AND TILDE|[[Ỗ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED8|U+1ED8 LATIN CAPITAL LETTER O WITH CIRCUMFLEX AND DOT BELOW|[[Ộ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE2|U+1EE2 LATIN CAPITAL LETTER O WITH HORN AND DOT BELOW|[[Ợ]]|style=background:#FFD}}
|{{chset-cell1|u=1EDA|U+1EDA LATIN CAPITAL LETTER O WITH HORN AND ACUTE|[[Ớ]]|style=background:#FFD}}
|{{chset-cell1|u=1EDC|U+1EDC LATIN CAPITAL LETTER O WITH HORN AND GRAVE|[[Ờ]]|style=background:#FFD}}
|{{chset-cell1|u=1EDE|U+1EDE LATIN CAPITAL LETTER O WITH HORN AND HOOK ABOVE|[[Ở]]|style=background:#FFD}}
|{{chset-cell1|u=1ECA|U+1ECA LATIN CAPITAL LETTER I WITH DOT BELOW|[[Ị]]|style=background:#FFD}}
|{{chset-cell1|u=1ECE|U+1ECE LATIN CAPITAL LETTER O WITH HOOK ABOVE|[[Ỏ]]|style=background:#FFD}}
|{{chset-cell1|u=1ECC|U+1ECC LATIN CAPITAL LETTER O WITH DOT BELOW|[[Ọ]]|style=background:#FFD}}
|{{chset-cell1|u=1EC8|U+1EC8 LATIN CAPITAL LETTER I WITH HOOK ABOVE|[[Ỉ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE6|U+1EE6 LATIN CAPITAL LETTER U WITH HOOK ABOVE|[[Ủ]]|style=background:#FFD}}
|{{chset-cell1|u=0168|U+0168 LATIN CAPITAL LETTER U WITH TILDE|[[Ũ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE4|U+1EE4 LATIN CAPITAL LETTER U WITH DOT BELOW|[[Ụ]]|style=background:#FFD}}
|{{chset-cell1|u=1EF2|U+1EF2 LATIN CAPITAL LETTER Y WITH GRAVE|[[Ỳ]]|style=background:#FFD}}
|-
|{{chset-left1|Ax}}
|{{chset-cell1|u=00D5|U+00D5 LATIN CAPITAL LETTER O WITH TILDE|[[Õ]]|style=background:#FFD}}
|{{chset-cell1|u=1EAF|U+1EAF LATIN SMALL LETTER A WITH BREVE AND ACUTE|[[ắ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB1|U+1EB1 LATIN SMALL LETTER A WITH BREVE AND GRAVE|[[ằ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB7|U+1EB7 LATIN SMALL LETTER A WITH BREVE AND DOT BELOW|[[ặ]]|style=background:#FFD}}
|{{chset-cell1|u=1EA5|U+1EA5 LATIN SMALL LETTER A WITH CIRCUMFLEX AND ACUTE|[[ấ]]|style=background:#FFD}}
|{{chset-cell1|u=1EA7|U+1EA7 LATIN SMALL LETTER A WITH CIRCUMFLEX AND GRAVE|[[ầ]]|style=background:#FFD}}
|{{chset-cell1|u=1EA9|U+1EA9 LATIN SMALL LETTER A WITH CIRCUMFLEX AND HOOK ABOVE|[[ẩ]]|style=background:#FFD}}
|{{chset-cell1|u=1EAD|U+1EAD LATIN SMALL LETTER A WITH CIRCUMFLEX AND DOT BELOW|[[ậ]]|style=background:#FFD}}
|{{chset-cell1|u=1EBD|U+1EBD LATIN SMALL LETTER E WITH TILDE|[[ẽ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB9|U+1EB9 LATIN SMALL LETTER E WITH DOT BELOW|[[ẹ]]|style=background:#FFD}}
|{{chset-cell1|u=1EBF|U+1EBF LATIN SMALL LETTER E WITH CIRCUMFLEX AND ACUTE|[[ế]]|style=background:#FFD}}
|{{chset-cell1|u=1EC1|U+1EC1 LATIN SMALL LETTER E WITH CIRCUMFLEX AND GRAVE|[[ề]]|style=background:#FFD}}
|{{chset-cell1|u=1EC3|U+1EC3 LATIN SMALL LETTER E WITH CIRCUMFLEX AND HOOK ABOVE|[[ể]]|style=background:#FFD}}
|{{chset-cell1|u=1EC5|U+1EC5 LATIN SMALL LETTER E WITH CIRCUMFLEX AND TILDE|[[ễ]]|style=background:#FFD}}
|{{chset-cell1|u=1EC7|U+1EC7 LATIN SMALL LETTER E WITH CIRCUMFLEX AND DOT BELOW|[[ệ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED1|U+1ED1 LATIN SMALL LETTER O WITH CIRCUMFLEX AND ACUTE|[[ố]]|style=background:#FFD}}
|-
|{{chset-left1|Bx}}
|{{chset-cell1|u=1ED3|U+1ED3 LATIN SMALL LETTER O WITH CIRCUMFLEX AND GRAVE|[[ồ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED5|U+1ED5 LATIN SMALL LETTER O WITH CIRCUMFLEX AND HOOK ABOVE|[[ổ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED7|U+1ED7 LATIN SMALL LETTER O WITH CIRCUMFLEX AND TILDE|[[ỗ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE0|U+1EE0 LATIN CAPITAL LETTER O WITH HORN AND TILDE|[[Ỡ]]|style=background:#FFD}}
|{{chset-cell1|u=01A0|U+01A0 LATIN CAPITAL LETTER O WITH HORN|[[Ơ]]|style=background:#FFD}}
|{{chset-cell1|u=1ED9|U+1ED9 LATIN SMALL LETTER O WITH CIRCUMFLEX AND DOT BELOW|[[ộ]]|style=background:#FFD}}
|{{chset-cell1|u=1EDD|U+1EDD LATIN SMALL LETTER O WITH HORN AND GRAVE|[[ờ]]|style=background:#FFD}}
|{{chset-cell1|u=1EDF|U+1EDF LATIN SMALL LETTER O WITH HORN AND HOOK ABOVE|[[ở]]|style=background:#FFD}}
|{{chset-cell1|u=1ECB|U+1ECB LATIN SMALL LETTER I WITH DOT BELOW|[[ị]]|style=background:#FFD}}
|{{chset-cell1|u=1EF0|U+1EF0 LATIN CAPITAL LETTER U WITH HORN AND DOT BELOW|[[Ự]]|style=background:#FFD}}
|{{chset-cell1|u=1EE8|U+1EE8 LATIN CAPITAL LETTER U WITH HORN AND ACUTE|[[Ứ]]|style=background:#FFD}}
|{{chset-cell1|u=1EEA|U+1EEA LATIN CAPITAL LETTER U WITH HORN AND GRAVE|[[Ừ]]|style=background:#FFD}}
|{{chset-cell1|u=1EEC|U+1EEC LATIN CAPITAL LETTER U WITH HORN AND HOOK ABOVE|[[Ử]]|style=background:#FFD}}
|{{chset-cell1|u=01A1|U+01A1 LATIN SMALL LETTER O WITH HORN|[[ơ]]|style=background:#FFD}}
|{{chset-cell1|u=1EDB|U+1EDB LATIN SMALL LETTER O WITH HORN AND ACUTE|[[ớ]]|style=background:#FFD}}
|{{chset-cell1|u=01AF|U+01AF LATIN CAPITAL LETTER U WITH HORN|[[Ư]]|style=background:#FFD}}
|-
|{{chset-left1|Cx}}
|{{chset-cell1|U+00C0 LATIN CAPITAL LETTER A WITH GRAVE|[[À]]}}
|{{chset-cell1|U+00C1 LATIN CAPITAL LETTER A WITH ACUTE|[[Á]]}}
|{{chset-cell1|U+00C2 LATIN CAPITAL LETTER A WITH CIRCUMFLEX|[[Â]]}}
|{{chset-cell1|U+00C3 LATIN CAPITAL LETTER A WITH TILDE|[[Ã]]}}
|{{chset-cell1|u=1EA2|U+1EA2 LATIN CAPITAL LETTER A WITH HOOK ABOVE|[[Ả]]|style=background:#FFD}}
|{{chset-cell1|u=0102|U+0102 LATIN CAPITAL LETTER A WITH BREVE|[[Ă]]|style=background:#FFD}}
|{{chset-cell1|u=1EB3|U+1EB3 LATIN SMALL LETTER A WITH BREVE AND HOOK ABOVE|[[ẳ]]|style=background:#FFD}}
|{{chset-cell1|u=1EB5|U+1EB5 LATIN SMALL LETTER A WITH BREVE AND TILDE|[[ẵ]]|style=background:#FFD}}
|{{chset-cell1|U+00C8 LATIN CAPITAL LETTER E WITH GRAVE|[[È]]}}
|{{chset-cell1|U+00C9 LATIN CAPITAL LETTER E WITH ACUTE|[[É]]}}
|{{chset-cell1|U+00CA LATIN CAPITAL LETTER E WITH CIRCUMFLEX|[[Ê]]}}
|{{chset-cell1|u=1EBA|U+1EBA LATIN CAPITAL LETTER E WITH HOOK ABOVE|[[Ẻ]]|style=background:#FFD}}
|{{chset-cell1|U+00CC LATIN CAPITAL LETTER I WITH GRAVE|[[Ì]]}}
|{{chset-cell1|U+00CD LATIN CAPITAL LETTER I WITH ACUTE|[[Í]]}}
|{{chset-cell1|u=0128|U+0128 LATIN CAPITAL LETTER I WITH TILDE|[[Ĩ]]|style=background:#FFD}}
|{{chset-cell1|u=1EF3|U+1EF3 LATIN SMALL LETTER Y WITH GRAVE|[[ỳ]]|style=background:#FFD}}
|-
|{{chset-left1|Dx}}
|{{chset-cell1|u=0110|U+0110 LATIN CAPITAL LETTER D WITH STROKE|[[Đ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE9|U+1EE9 LATIN SMALL LETTER U WITH HORN AND ACUTE|[[ứ]]|style=background:#FFD}}
|{{chset-cell1|U+00D2 LATIN CAPITAL LETTER O WITH GRAVE|[[Ò]]}}
|{{chset-cell1|U+00D3 LATIN CAPITAL LETTER O WITH ACUTE|[[Ó]]}}
|{{chset-cell1|U+00D4 LATIN CAPITAL LETTER O WITH CIRCUMFLEX|[[Ô]]}}
|{{chset-cell1|u=1EA1|U+1EA1 LATIN SMALL LETTER A WITH DOT BELOW|[[ạ]]|style=background:#FFD}}
|{{chset-cell1|u=1EF7|U+1EF7 LATIN SMALL LETTER Y WITH HOOK ABOVE|[[ỷ]]|style=background:#FFD}}
|{{chset-cell1|u=1EEB|U+1EEB LATIN SMALL LETTER U WITH HORN AND GRAVE|[[ừ]]|style=background:#FFD}}
|{{chset-cell1|u=1EED|U+1EED LATIN SMALL LETTER U WITH HORN AND HOOK ABOVE|[[ử]]|style=background:#FFD}}
|{{chset-cell1|U+00D9 LATIN CAPITAL LETTER U WITH GRAVE|[[Ù]]}}
|{{chset-cell1|U+00DA LATIN CAPITAL LETTER U WITH ACUTE|[[Ú]]}}
|{{chset-cell1|u=1EF9|U+1EF9 LATIN SMALL LETTER Y WITH TILDE|[[ỹ]]|style=background:#FFD}}
|{{chset-cell1|u=1EF5|U+1EF5 LATIN SMALL LETTER Y WITH DOT BELOW|[[ỵ]]|style=background:#FFD}}
|{{chset-cell1|U+00DD LATIN CAPITAL LETTER Y WITH ACUTE|[[Ý]]}}
|{{chset-cell1|u=1EE1|U+1EE1 LATIN SMALL LETTER O WITH HORN AND TILDE|[[ỡ]]|style=background:#FFD}}
|{{chset-cell1|u=01B0|U+01B0 LATIN SMALL LETTER U WITH HORN|[[ư]]|style=background:#FFD}}
|-
|{{chset-left1|Ex}}
|{{chset-cell1|U+00E0 LATIN SMALL LETTER A WITH GRAVE|[[à]]}}
|{{chset-cell1|U+00E1 LATIN SMALL LETTER A WITH ACUTE|[[á]]}}
|{{chset-cell1|U+00E2 LATIN SMALL LETTER A WITH CIRCUMFLEX|[[â]]}}
|{{chset-cell1|U+00E3 LATIN SMALL LETTER A WITH TILDE|[[ã]]}}
|{{chset-cell1|u=1EA3|U+1EA3 LATIN SMALL LETTER A WITH HOOK ABOVE|[[ả]]|style=background:#FFD}}
|{{chset-cell1|u=0103|U+0103 LATIN SMALL LETTER A WITH BREVE|[[ă]]|style=background:#FFD}}
|{{chset-cell1|u=1EEF|U+1EEF LATIN SMALL LETTER U WITH HORN AND TILDE|[[ữ]]|style=background:#FFD}}
|{{chset-cell1|u=1EAB|U+1EAB LATIN SMALL LETTER A WITH CIRCUMFLEX AND TILDE|[[ẫ]]|style=background:#FFD}}
|{{chset-cell1|U+00E8 LATIN SMALL LETTER E WITH GRAVE|[[è]]}}
|{{chset-cell1|U+00E9 LATIN SMALL LETTER E WITH ACUTE|[[é]]}}
|{{chset-cell1|U+00EA LATIN SMALL LETTER E WITH CIRCUMFLEX|[[ê]]}}
|{{chset-cell1|u=1EBB|U+1EBB LATIN SMALL LETTER E WITH HOOK ABOVE|[[ẻ]]|style=background:#FFD}}
|{{chset-cell1|U+00EC LATIN SMALL LETTER I WITH GRAVE|[[ì]]}}
|{{chset-cell1|U+00ED LATIN SMALL LETTER I WITH ACUTE|[[í]]}}
|{{chset-cell1|u=0129|U+0129 LATIN SMALL LETTER I WITH TILDE|[[ĩ]]|style=background:#FFD}}
|{{chset-cell1|u=1EC9|U+1EC9 LATIN SMALL LETTER I WITH HOOK ABOVE|[[ỉ]]|style=background:#FFD}}
|-
|{{chset-left1|Fx}}
|{{chset-cell1|u=0111|U+0111 LATIN SMALL LETTER D WITH STROKE|[[đ]]|style=background:#FFD}}
|{{chset-cell1|u=1EF1|U+1EF1 LATIN SMALL LETTER U WITH HORN AND DOT BELOW|[[ự]]|style=background:#FFD}}
|{{chset-cell1|U+00F2 LATIN SMALL LETTER O WITH GRAVE|[[ò]]}}
|{{chset-cell1|U+00F3 LATIN SMALL LETTER O WITH ACUTE|[[ó]]}}
|{{chset-cell1|U+00F4 LATIN SMALL LETTER O WITH CIRCUMFLEX|[[ô]]}}
|{{chset-cell1|U+00F5 LATIN SMALL LETTER O WITH TILDE|[[õ]]}}
|{{chset-cell1|u=1ECF|U+1ECF LATIN SMALL LETTER O WITH HOOK ABOVE|[[ỏ]]|style=background:#FFD}}
|{{chset-cell1|u=1ECD|U+1ECD LATIN SMALL LETTER O WITH DOT BELOW|[[ọ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE5|U+1EE5 LATIN SMALL LETTER U WITH DOT BELOW|[[ụ]]|style=background:#FFD}}
|{{chset-cell1|U+00F9 LATIN SMALL LETTER U WITH GRAVE|[[ù]]}}
|{{chset-cell1|U+00FA LATIN SMALL LETTER U WITH ACUTE|[[ú]]}}
|{{chset-cell1|u=0169|U+0169 LATIN SMALL LETTER U WITH TILDE|[[ũ]]|style=background:#FFD}}
|{{chset-cell1|u=1EE7|U+1EE7 LATIN SMALL LETTER U WITH HOOK ABOVE|[[ủ]]|style=background:#FFD}}
|{{chset-cell1|U+00FD LATIN SMALL LETTER Y WITH ACUTE|[[ý]]}}
|{{chset-cell1|u=1EE3|U+1EE3 LATIN SMALL LETTER O WITH HORN AND DOT BELOW|[[ợ]]|style=background:#FFD}}
|{{chset-cell1|u=1EEE|U+1EEE LATIN CAPITAL LETTER U WITH HORN AND TILDE|[[Ữ]]|style=background:#FFD}}
|}
{{legend|#FFD|Differences from [[ISO-8859-1]]}}

==See also==
*[[ASCII]]
*[[Vietnamese Quoted-Readable]] (VIQR)
*[[Vietnamese Standard Code for Information Interchange]] (VSCII)
*[[Windows-1258]]

==References==
{{Reflist}}

==Further reading==
*<!-- <ref name="Flohr_2016_VISCII"> -->{{cite web |title=Locale::RecodeData::VISCII - Conversion routines for VISCII |author-first=Guido |author-last=Flohr |work=[[CPAN]] libintl-perl |date=2016 |orig-year=2006<!-- 2002 --> |url=http://search.cpan.org/~guido/libintl-perl/lib/Locale/RecodeData/VISCII.pm |access-date=2017-01-14 |url-status=live |archive-url=https://web.archive.org/web/20170114231327/http://search.cpan.org/~guido/libintl-perl/lib/Locale/RecodeData/VISCII.pm |archive-date=2017-01-14}}<!-- </ref> -->
*https://www.math.nmsu.edu/~mleisher/Software/csets/VISCII.TXT<!-- https://web.archive.org/web/20170219001026/https://www.math.nmsu.edu/~mleisher/Software/csets/VISCII.TXT -->

==External links==
*{{IETF RFC|1456|link=no}} - Conventions for Encoding the Vietnamese Language
*[http://vietstd.sf.net/ Vietnamese-Standardization Working Group] based in California
*[http://vietstd.sf.net/document/report92.htm Viet-Std Report 1992]
*[http://www.xmlunify.com/angiang_ss1.htm AnGiang Software]
*[https://web.archive.org/web/20201125073651/http://ftp.monash.edu.au/pub/vietnam/ VISCII-compliant software and fonts for MS-DOS and Windows]
*[https://web.archive.org/web/20190912235458/http://ftp.monash.edu.au/pub/vietnam/unix/ VISCII-compliant software, libraries, and fonts for Unix]
*[http://winvnkey.sf.net WinVNKey], Vietnamese keyboard driver for Windows supporting multinational character sets, including VISCII
*[http://macvnkey.sf.net MacVNKey], VISCII-compliant keyboard driver for Macintosh classic

{{Character encodings}}
[[Category:Computer-related introductions in 1992]]
[[Category:1992 establishments in California]]
[[Category:Character sets]]
[[Category:Vietnamese writing systems]]