Character Sets

Last Updated

• 2026-10-02

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Character Sets

Registration Procedure(s)

• Expert Review

Expert(s)

• Martin Dürst

Reference

• RFC 2978: IANA Charset Registration Procedures

Note

Registration requests must be sent to the subscriber-only ietf-charsets@iana.org mailing list. The designated expert will forward approved requests to IANA.

Subscribe by email: mailto:ietf-charsets-join@iana.org View the archive or subscribe online: Mailing list interface

If you have any questions, please contact iana@iana.org.

Note

These are the official names for character sets that may be used in the Internet and may be referred to in Internet documentation. These names are expressed in ANSI_X3.4-1968 which is commonly called US-ASCII or simply ASCII. The character set most commonly use in the Internet and used especially in protocol standards is US-ASCII, this is strongly encouraged. The use of the name US-ASCII is also encouraged.

The character set names may be up to 40 characters taken from the printable characters of US-ASCII. However, no distinction is made between use of upper and lower case letters.

The MIBenum value is a unique value for use in MIBs to identify coded character sets.

The value space for MIBenum values has been divided into three regions. The first region (3-999) consists of coded character sets that have been standardized by some standard setting organization. This region is intended for standards that do not have subset implementations. The second region (1000-1999) is for the Unicode and ISO/IEC 10646 coded character sets together with a specification of a (set of) sub-repertoires that may occur. The third region (>1999) is intended for vendor specific coded character sets.

    Assigned MIB enum Numbers
    -------------------------
    0-2             Reserved
    3-999           Set By Standards Organizations
    1000-1999       Unicode / 10646
    2000-2999       Vendor

The aliases that start with "cs" have been added for use with the IANA-CHARSET-MIB as originally defined in RFC 3808, and as currently maintained by IANA at IANA-CHARSET-MIB. Note that the ianacharset-mib needs to be kept in sync with this registry. These aliases that start with "cs" contain the standard numbers along with suggestive names in order to facilitate applications that want to display the names in user interfaces. The "cs" stands for character set and is provided for applications that need a lower case first letter but want to use mixed case thereafter that cannot contain any special characters, such as underbar ("_") and dash ("-").

If the character set is from an ISO standard, its cs alias is the ISO standard number or name. If the character set is not from an ISO standard, but is registered with ISO (IPSJ/ITSCJ is the current ISO Registration Authority), the ISO Registry number is specified as ISOnnn followed by letters suggestive of the name or standards number of the code set. When a national or international standard is revised, the year of revision is added to the cs alias of the new character set entry in the IANA Registry in order to distinguish the revised character set from the original character set.

Available Formats

• CSV