Character Mnemonics and Character Sets
RFC 1345

Document Type RFC - Informational (June 1992; Errata)
Last updated 2013-03-02
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Network Working Group                                        K. Simonsen
Request for Comments: 1345                   Rationel Almen Planlaegning
                                                               June 1992

                  Character Mnemonics & Character Sets

Status of the Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

Summary

   This memo lists a selection of characters and their presence in some
   coded character sets. To facilitate the coded character set
   tabulations an unambiguous mnemonic for each character is used, and a
   format for tabulating the coded character sets is defined. The coded
   character sets are given names for easy reference. A family of coded
   character sets called the mnemonic character sets and conversion
   between these coded character set without information loss is
   defined.

   The character set names are registered with the Internet Assigned
   Numbers Authority (IANA).  Additional character sets not described in
   this memo should be registered with the IANA. This memo may be
   updated periodically, or additional specifications may be published,
   to reflect other coded character sets.

   Please send any comments including comments about the accuracy of the
   tables to the author, Keld Simonsen <Keld.Simonsen@dkuug.dk>.

1.  INTRODUCTION

   With the growing internationalization of the Internet, support for
   many coded character sets is required. It is the intention of this
   memo to document precisely the mapping between all characters and
   their corresponding coded representations in various coded character
   sets, and give names to these coded character sets, so they can be
   referenced unambiguously in Internet standards.

   This memo does not indicate anything about the validity of using
   these specifications in any Internet standard, so you should consult
   each individual Internet standard to see which coded character sets
   and names are allowed there.

   Unambiguous character mnemonics are specified, which provide a
   practical way of identifying a character, without reference to a
   coded character set and its code in this coded character set.  The
   mnemonics are written in a minimal set of characters, namely the
   invariant 83 graphical characters of ISO 646, which is a kind of
   greatest common subset to be found between the majority of coded

Simonsen                                                        [Page 1]
RFC 1345          Character Mnemonics & Character Sets         June 1992

   character sets, including ASCII, national variants of the ISO 646 7-
   bit character set and various EBCDICs.  In addition, the numeric
   value of the coded representations of all these characters are the
   same in all coded character sets compatible with ISO standards.  All
   of them except two, EXCLAMATION MARK and QUOTATION MARK, have the
   same coded representation in all variants of EBCDIC.  This minimal
   set of characters is called the reference character set in this memo.

   The mnemonics can be used in Internet standards for easy and
   unambiguous reference, and they can also serve as a fallback
   representation in various Internet specifications.

   The coded character sets covered include all parts of ISO 8859, ISO
   6937-2 and all ISO 646 conforming coded character sets in the ISO
   character set registry managed by ECMA according to ISO 2375.  Almost
   all graphic coded character sets in the ECMA registry (1) are
   covered.  The graphic coded character sets not included are registry
   numbers 31, 38, 39, 53, 59, 68, 71, 72, 129 and 137.  In addition
   many vendor defined character sets are covered, including PC
   codepages (4), (7), (8), many EBCDIC character sets (4), (5), (6) and
   HP, DEC and Apple character sets (8), (9), (10), (13), (14).  The
   East-Asian 16-bit character sets from the ECMA registry is also
   included in this memo.

2.  CHARACTER MNEMONICS

2.1  General Syntax

   The character mnemonics are taken from the ISO committee draft (CD)
   of the POSIX.2 standard (3).  They are classified into two groups:

   1. A group with two-character mnemonics
      - Primarily intended for alphabetic scripts like Latin, Greek,
        Cyrillic, Hebrew and Arabic, and special characters.
   2. A group with variable-length mnemonics
      - primarily intended for non-alphabetic scripts like Japanese and
        Chinese, but also used for some accented letters and special
        characters.

   In the two-character mnemonics, all invariant graphic character in
   the ISO 646 character codes except "&" are used, i.e. the following
   characters:

           ! "     %   ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
             A B C D E F G H I J K L M N O P Q R S T U V W X Y Z       _
             a b c d e f g h i j k l m n o p q r s t u v w x y z

   The character "_" is not used as the first character.
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