Editing Big5 (section)

===Vendor extensions===
====ETen extensions====
In the [[ETen Chinese System|ETen]] (倚天) Chinese operating system, the following code points are added, to add support for some characters present in the [[IBM 5550]]'s code page but absent from generic Big5:

* <code>0xA3C0</code>–<code>0xA3E0</code>: 33 control characters.
* <code>0xC6A1</code>–<code>0xC875</code>: circle 1–10, bracket 1–10, [[Roman numerals]] 1–9 (i–ix), CJK radical glyphs, Japanese [[hiragana]], Japanese [[katakana]], [[Cyrillic]] characters
* <code>0xF9D6</code>–<code>0xF9FE</code>: the characters '[[wikt:碁|碁]]', '[[wikt:銹|銹]]', '[[wikt:恒|恒]]', '[[wikt:裏|裏]]', '[[wikt:墻|墻]]', '[[wikt:粧|粧]]' and '[[wikt:嫺|嫺]]', followed by 34 additional [[semigraphic]] symbols.

In some versions of ETen, there are extra graphical symbols and [[simplified Chinese characters]].

====Microsoft code pages====
{{Main|Code page 950}}

[[Microsoft]] (微軟) created its own version of Big5 extension as [[code page 950]] for use with [[Microsoft Windows]], which supports the F9D6–F9FE code points from ETEN's extensions. In some versions of Windows, the [[euro]] [[Euro sign|currency symbol]] is mapped to Big-5 code point A3E1.

After installing Microsoft's [http://www.microsoft.com/hk/hkscs/default.aspx HKSCS patch] on top of traditional Chinese Windows (or any version of Windows 2000 and above with proper language pack), applications using code page 950 automatically use a hidden code page 951 table. The table supports all code points in HKSCS-2001, except for the compatibility code points specified by the standard.<ref>{{Cite web|url=http://me.abelcheung.org/2006/09/12/what-is-cp951/|title=狗爺語錄 » Blog Archive » What is Code Page 951 (CP951)?<!-- Bot generated title -->|access-date=2006-09-27|archive-url=https://web.archive.org/web/20070222070938/http://me.abelcheung.org/2006/09/12/what-is-cp951/|archive-date=2007-02-22|url-status=dead}}</ref>

====IBM code pages====
In contrast to Microsoft's code page 950, IBM's [[CCSID]] 950 comprises single byte code page 1114 (CCSID 1114) and double byte code page 947 (CCSID 947).<ref name="ccsid950">{{cite web|title=CCSID 950 information document|archive-url=https://web.archive.org/web/20141202001630/http://www-01.ibm.com/software/globalization/ccsid/ccsid950.html|archive-date=2014-12-02|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid950.html}}</ref><ref>{{cite web|title=CCSID 1114 information document|archive-url=https://web.archive.org/web/20160327100728/http://www-01.ibm.com/software/globalization/ccsid/ccsid1114.html|archive-date=2016-03-27|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid1114.html}}</ref><ref>{{cite web|title=CCSID 947 information document|archive-url=https://web.archive.org/web/20141201232116/http://www-01.ibm.com/software/globalization/ccsid/ccsid947.html|archive-date=2014-12-01|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid947.html}}</ref> It incorporates ETEN extensions for lead bytes {{mono|0xA3}},<ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=A3&s=ALL#layout|title=Lead byte A3: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> {{mono|0xC6}},<ref name="rfc1922">{{citation|mode=cs1|id=<nowiki>RFC 1922</nowiki>|title=Chinese Character Encoding for Internet Messages|url=https://tools.ietf.org/html/rfc1922|first1=HF.|last1=Zhu|first2=DY.|last2=Hu|first3=ZG.|last3=Wang|first4=TC.|last4=Kao|first5=WCH.|last5=Chang|first6=M.|last6=Crispin|publisher=[[IETF]]|work=Requests for Comments|date=1996|doi=10.17487/rfc1922|doi-access=|access-date=2022-01-01|archive-date=2021-04-29|archive-url=https://web.archive.org/web/20210429165037/https://tools.ietf.org/html/rfc1922|url-status=live|url-access=subscription}}</ref><ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=C6&s=ALL#layout|title=Lead byte C6: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> {{mono|0xC7}}<ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=C7&s=ALL#layout|title=Lead byte C7: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> and {{mono|0xC8}},<ref name="rfc1922"/><ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=C8&s=ALL#layout|title=Lead byte C8: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> while omitting those with lead byte {{mono|0xF9}} (which Microsoft includes), mapping them instead to the [[Private Use Area]] as user-defined characters.<ref name="rfc1922"/><ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=F9&s=ALL#layout|title=Lead byte F9: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> It also includes two non-ETEN extension regions with trail bytes {{mono|0x81–A0}}, i.e. outside the usual Big5 trail byte range but similar to the Big5+ trail byte range: area 5 has lead bytes {{mono|0xF2–F9}} and contains IBM-selected characters, while area 9 has lead bytes {{mono|0x81–8C}} and is a user-defined region.<ref>{{cite web|url=https://public.dhe.ibm.com/as400/products/clientaccess/win32/files/globalization/T_Chinese_big51999.pdf|title=IBM Traditional Chinese Graphic Character Set for IBM BIG-5 Code|publisher=[[IBM]]|year=1999|id=C-H 3-3220-131 1999-04|access-date=2022-01-01|archive-date=2021-11-22|archive-url=https://web.archive.org/web/20211122211354/https://public.dhe.ibm.com/as400/products/clientaccess/win32/files/globalization/T_Chinese_big51999.pdf|url-status=live}}</ref>

IBM refers to the euro sign update of their Big-5 variant as CCSID 1370, which includes both single-byte ({{mono|0x80}}) and double-byte ({{mono|0xA3E1}}) euro signs.<ref name="ccsid1370">{{cite web|title=CCSID 1370 information document|archive-url=https://web.archive.org/web/20160327104212/http://www-01.ibm.com/software/globalization/ccsid/ccsid1370.html|archive-date=2016-03-27|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid1370.html}}</ref> It comprises single byte code page 1114 (CCSID 5210) and double byte code page 947 (CCSID 21427).<ref name="ccsid1370"/><ref>{{cite web|title=CCSID 5210 information document|archive-url=https://web.archive.org/web/20141129231704/http://www-01.ibm.com/software/globalization/ccsid/ccsid5210.html|archive-date=2014-11-29|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid5210.html}}</ref><ref>{{cite web|title=CCSID 21427 information document|archive-url=https://web.archive.org/web/20160327035914/http://www-01.ibm.com/software/globalization/ccsid/ccsid21427.html|archive-date=2016-03-27|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid21427.html}}</ref> For better compatibility with Microsoft's variant in [[IBM Db2]], IBM also define the pure double-byte code page 1372<ref>{{cite web|archive-url=https://web.archive.org/web/20160317015819/http://www-01.ibm.com/software/globalization/cp/cp01372.html|archive-date=2016-03-17|url=http://www-01.ibm.com/software/globalization/cp/cp01372.html|url-status=dead|title=CPGID 01372: MS T-Chinese Big-5 (Special for DB2)|work=IBM Globalization - Code page identifiers}}</ref> and the associated variable-width CCSID 1373, which corresponds to Microsoft's code page 950.<ref>{{cite web|url=http://icu-project.org/icu-bin/convexp?conv=ibm-1373_P100-2002|title=ibm-1373_P100-2002|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]|access-date=2022-01-01|archive-date=2021-05-26|archive-url=https://web.archive.org/web/20210526173749/https://icu4c-demos.unicode.org/icu-bin/convexp?conv=ibm-1373_P100-2002|url-status=live}}</ref>

IBM assigns CCSID 5471 to the HKSCS-2001 Big5 code page (with CPGID 1374 as CCSID 5470 as the double byte component),<ref>{{cite web|archive-url=https://web.archive.org/web/20141129233053/http://www-01.ibm.com/software/globalization/ccsid/ccsid5471.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid5471.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 5471: Mixed Big-5 ext for HKSCS-2001}}</ref><ref>{{Citation|title=International Components for Unicode (ICU), ibm-5471_P100-2006.ucm|url=https://github.com/unicode-org/icu/blob/master/icu4c/source/data/mappings/ibm-5471_P100-2006.ucm|date=2007-05-09|access-date=2022-01-01|archive-date=2023-08-13|archive-url=https://web.archive.org/web/20230813202101/https://github.com/unicode-org/icu/blob/main/icu4c/source/data/mappings/ibm-5471_P100-2006.ucm|url-status=live}}</ref> CCSID 9567 to the HKSCS-2004 code page (with CPGID 1374 as CCSID 9566 as the double byte component),<ref>{{cite web|archive-url=https://web.archive.org/web/20141129212819/http://www-01.ibm.com/software/globalization/ccsid/ccsid9567.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid9567.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 9567: Mixed Big-5 ext for HKSCS-2004}}</ref> and CCSID 13663 to the HKSCS-2008 code page (with CPGID 1374 as CCSID 13662 as the double byte component),<ref>{{cite web|archive-url=https://web.archive.org/web/20141129213320/http://www-01.ibm.com/software/globalization/ccsid/ccsid13663.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid13663.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 13663: Mixed Big-5 ext for HKSCS-2008}}</ref> while CCSID 1375 is assigned to a growing HKSCS code page, currently equivalent to CCSID 13663.<ref>{{cite web|archive-url=https://web.archive.org/web/20141129231410/http://www-01.ibm.com/software/globalization/ccsid/ccsid1375.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid1375.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 1375: Mixed Big-5 ext for HKSCS}}</ref>

====ChinaSea font====
[[ChinaSea]] fonts (中國海字集)<ref>{{cite web|author=黃國書|url=http://ftp.isu.edu.tw/pub/Windows/Chinese/font/chinasea/csw10_exp.txt|title=Chinasea 1.0 中國海字集|publisher=ISU FTP|access-date=2016-12-05|archive-url=https://web.archive.org/web/20050319032136/http://ftp.isu.edu.tw/pub/Windows/Chinese/font/chinasea/csw10_exp.txt|archive-date=2005-03-19|url-status=dead}}</ref> are Traditional Chinese fonts made by ChinaSea. The fonts are rarely sold separately, but are bundled with other products, such as the Chinese version of [[Microsoft Office 97]]. The fonts support Japanese kana, [[kokuji]], and other characters missing in Big-5. As a result, the ChinaSea extensions have become more popular than the government-supported extensions.{{as of?|date=May 2019}} Some Hong Kong [[Bulletin board system|BBSes]] had used encodings in ChinaSea fonts before the introduction of HKSCS.

===='Sakura' font====
The [https://web.archive.org/web/20060904023817/http://input.foruto.com/jptxt/ 'Sakura' font] (日和字集 Sakura Version) is developed in Hong Kong and is designed to be compatible with HKSCS. It adds support for [[kokuji]] and proprietary dingbats (including [[Doraemon]]) not found in HKSCS.

====Unicode-at-on====
Unicode-at-on ([[:zh:Unicode補完計畫|Unicode補完計畫]]), formerly BIG5 extension, extends BIG-5 by altering code page tables, but uses the ChinaSea extensions starting with version 2. However, with the bankruptcy of ChinaSea, late development, and the increasing popularity of HKSCS and [[Unicode]] (the project is not compatible with HKSCS), the success of this extension is limited at best.

Despite the problems, characters previously mapped to Unicode Private Use Area are remapped to the standardized equivalents when exporting characters to Unicode format.

====OPG====
The web sites of the [[Oriental Daily News]] and [[Sun Daily]], belonging to the [[Oriental Press Group Limited]] (東方報業集團有限公司) in Hong Kong, used a downloadable font with a different Big-5 extension coding than the HKSCS.