(Last updated 23 January 2004)

Charset name: KOI7-switched

Charset aliases: None

Suitability for use in MIME text: Yes

Published specifications:

The charset is a 7-bit Character Encoding Scheme (CES) as follows. Each octet
MUST have value between 0 and 177 octal, inclusive. Octets with values 0
through 15 octal (inclusive) and 20 through 177 octal (inclusive) are to be
interpreted per one of two Coded Character Sets (CCS's): ISO_646.irv:1983 and
ISO_5427. The CCS to use is determined by the switch state. Octet with value 16
octal selects ISO_5427 and octet with value 17 octal selects ISO_646.irv:1983.
The initial CCS is ISO_646.irv:1983.

HISTORICAL NOTE: This charset was used in Soviet computer systems as a
replacement for ASCII. It was intended to do for Soviet computer systems what
ASCII does for American ones. The only additional feature required by the
former is encoding of Russian letters. To achieve the above goal Soviet
standards defined several 7-bit charsets, all of which were called KOI-7.
KOI-7 N0 was the Soviet name for ISO 646 IRV, which is the same as US-ASCII
except for rendering 44 octal as the international currency symbol instead of
the dollar sign, and KOI-7 N1 (registered as ISO_5427) had English letters and
some special characters replaced with Russian letters. The two KOI-7 CCS's were
commonly used with the CES described above to achieve functionality which is a
superset of ASCII and Russian.

An ISO 2022 compliant terminal can be prepared for displaying KOI7-switched
text with the following sequence:

ESC ( @ ESC ) N LS0

Additional information:

Person & email address to contact for further information:

Michael Sokolov
International Free Computing Task Force (IFCTF)
msokolov&ivan.Harhan.ORG

Intended usage: LIMITED USE

This charset is not as convenient as the several 8-bit CCS's available for
Latin/Cyrillic encoding, however, when a 7-bit communication channel must be
used using this charset is much more efficient than using an 8-bit CCS such as
ISO_8859-5 or KOI-8 and then encoding it with a scheme such as uuencode, MIME
base64, or MIME quoted-printable.

[Record created 23 January 2004]