HTTP: The Definitive Guide

H.1 MIME Charset Registry

MIME charset tags are registered with the IANA (http://www.iana.org/numbers.htm). The charset registry is a flat-file text database of records. Each record contains a charset name, reference citations, a unique MIB number, a source description, and a list of aliases. A name or alias may be flagged "preferred MIME name."

Here is the record for US-ASCII:

Name: ANSI_X3.4-1968 [RFC1345, KXS2]^

MIBenum: 3

Source: ECMA registry

Alias: iso-ir-6

Alias: ANSI_X3.4-1986

Alias: ISO_646.irv:1991

Alias: ASCII

Alias: ISO646-US

Alias: US-ASCII (preferred MIME name)

Alias: us

Alias: IBM367

Alias: cp367

Alias: csASCII

The procedure for registering a charset with the IANA is documented in RFC 2978 (http://www.ietf.org/rfc/rfc2978.txt).