Chinese Character Encoding for Internet Messages (RFC1922)
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2019-Feb-12
Internet Society Requests For Comment (RFCs)
HF. Zhu: AUTHOR [+5]
This memo describes methods of transporting Chinese characters in Internet services which transport text, such as electronic mail [RFC-822], network news [RFC-1036], telnet [RFC-854] and the World Wide Web [RFC-1866]. This memo provides information for the Internet community. It does not specify an Internet standard.
Network Working Group HF. Zhu Request for Comments: 1922 Tsinghua U Category: Informational DY. Hu Tsinghua U ZG. Wang CITS TC. Kao III WCH. Chang III M. Crispin U Washington March 1996
Chinese Character Encoding for Internet Messages
Status of this Memo
This memo provides information for the Internet community. It does not specify an Internet standard. Distribution of this memo is unlimited.
This memo describes methods of transporting Chinese characters in Internet services which transport text, such as electronic mail [RFC-822], network news [RFC-1036], telnet [RFC-854] and the World Wide Web [RFC-1866].
As the use of Internet covers more and more Chinese people in the world, the need has increased for the ability to send documents containing Chinese characters on the Internet. The methods described in this document provide means of transporting existing Chinese character sets as well as leaving space for future extension.
This document describes two encodings, ISO-2022-CN and ISO-2022-CN-EXT. These are designed with interoperability in mind and are encouraged in this document for current Chinese interchange; they are 7-bit, support both simplified and traditional characters using both GB and CNS/Big5, and do not impose any unusual quoting requirements on ASCII characters.
As important related issues, this document gives detailed descriptions of the two encodings CN-GB and CN-Big5, and a brief description of ISO/IEC 10646 [ISO-10646]. CN-GB and CN-Big5 are
Zhu, et al Informational [Page 1]
RFC 1922 Chinese Character Encoding March 1996
currently used as the internal codes for Chinese documents. ISO-10646 is the universal multi-octet character set defined by ISO; we feel that in the future it may become the preferred technology for Chinese documents and electronic mail when it is widely available.
1. 7-bit Chinese encodings: ISO-2022-CN and ISO-2022-CN-EXT
ISO-2022-CN is based on ISO 2022 [ISO-2022], similar to earlier work on ISO-2022-JP [RFC-1468] and ISO-2022-KR [RFC-1557] for the Japanese and Korean languages respectively. It is 7-bit, and supports both simplified Chinese characters using GB 2312-80 [GB-2312] and traditional Chinese characters using the first two planes of CNS 11643 [CNS-11643], as well as ASCII [ASCII] characters.
ISO-2022-CN-EXT is a superset of ISO-2022-CN that additionally supports other GB character sets and planes of CNS 11643.
Since ISO-2022-CN and ISO-2022-CN-EXT are 7-bit encodings, they do not require the 8-bit SMTP extensions. ISO-2022-CN supports all the Chinese characters that appear in Big5 [BIG5].
The starting code of ISO-2022-CN is ASCII. ASCII and Chinese characters are distinguished by designations (ESC sequences) and shift functions.
Designations define the Chinese character sets used in the text. There are three kinds of designations: SOdesignation, SS2designation and SS3designation.
The SOdesignation is in the form ESC $ ) <F>, whe...