KOI-7 (КОИ-7) is a 7-bit

character encoding Character encoding is the process of assigning numbers to graphical character (computing), characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical v ...

, designed to cover Russian, which uses the

Cyrillic The Cyrillic script ( ) is a writing system used for various languages across Eurasia. It is the designated national script in various Slavic, Turkic, Mongolic, Uralic, Caucasian and Iranic-speaking countries in Southeastern Europe, Ea ...

alphabet. In Russian, KOI-7 stands for ''Kod Obmena Informatsiey, 7 bit'' (Код Обмена Информацией, 7 бит) which means "Code for Information Exchange, 7 bit". It was first standardized in GOST 13052-67 (with the 2nd revision GOST 13052-74 / ST SEV 356-76) and GOST 27463-87 / ST SEV 356-86. Shift Out (SO) and Shift In (SI)

control characters In computing and telecommunications, a control character or non-printing character (NPC) is a code point in a character set that does not represent a written character or symbol. They are used as in-band signaling to cause effects other than ...

are used in KOI-7, where SO starts printing Russian letters (KOI-7 N1), and SI starts printing

Latin letters The Latin script, also known as the Roman script, is a writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae in Magna Graecia. The Gree ...

again (KOI-7 N0), or for

lowercase Letter case is the distinction between the letters that are in larger uppercase or capitals (more formally ''majuscule'') and smaller lowercase (more formally '' minuscule'') in the written representation of certain languages. The writing system ...

and

uppercase Letter case is the distinction between the letters that are in larger uppercase or capitals (more formally ''#Majuscule, majuscule'') and smaller lowercase (more formally ''#Minuscule, minuscule'') in the written representation of certain langua ...

switching. This version is also known as KOI7-switched aka csKOI7switched. On

ISO 2022 ISO/IEC 2022 ''Information technology—Character code structure and extension techniques'', is an ISO/IEC standard in the field of character encoding. It is equivalent to the ECMA standard ECMA-35, the ANSI standard ANSI X3.41 and the Japanes ...

compatible

computer terminal A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. Most early computers only had a front panel to input or display ...

s KOI7-switched can be activated by the escape sequence ESC ( @ ESC ) N LS0. KOI-7 was used on machines like the

SM EVM SM EVM (СМ ЭВМ, abbreviation of Система Малых ЭВМ—literally System of Mini Computers) are several types of Soviet and Comecon minicomputers produced from 1975 through the 1980s. Most types of SM EVM are clones of DEC PDP-11 ...

(СМ ЭВМ) and

DVK DVK (, ''Interactive Computing Complex'') is a Soviet PDP-11-compatible personal computer. It was designed by the Research Institute of Precision Technology in Zelenograd. Overview The design is also known as Elektronika MS-0501 and Elektronika ...

(ДВК); KOI-7 N2 was utilized in the machine-language of the (Elektronika D3-28) as four-digit hexadecimal code, (BESM-6), where it was called ВКД, (internal data code). The encodings were also used on

RSX-11 RSX-11 is a discontinued family of multi-user real-time operating systems for PDP-11 computers created by Digital Equipment Corporation. In widespread use through the late 1970s and early 1980s, RSX-11 was influential in the development of later ...

RT-11 RT-11 (Real-time 11) is a discontinued small, low-end, single-user real-time operating system for the full line of Digital Equipment Corporation PDP-11 16-bit computers. RT-11 was first implemented in 1970. It was widely used for real-time compu ...

and similar systems.

KOI-7 N0

KOI-7 N0 (КОИ-7 Н0) is identical to the IRV set in

ISO 646 ISO/IEC 646 ''Information technology — ISO 7-bit coded character set for information interchange'', is an International Organization for Standardization, ISO/International Electrotechnical Commission, IEC standard in the ...

:1967. Compared to

US-ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...

, the

dollar sign The dollar sign, also known as the peso sign, is a currency symbol consisting of a Letter case, capital crossed with one or two vertical strokes ( or depending on typeface), used to indicate the unit of various currency, currencies around ...

("$") at code point 24 (_hex) was replaced by the

universal currency sign The currency sign is a character used to denote an unspecified currency. It can be described as a circle the size of a lowercase character with four short radiating arms at 45° (NE), 135° (SE), 225° (SW) and 315° (NW). It is raised slightl ...

"¤", but this was not maintained in all cases, in particular not after the fall of the

Iron Curtain The Iron Curtain was the political and physical boundary dividing Europe into two separate areas from the end of World War II in 1945 until the end of the Cold War in 1991. On the east side of the Iron Curtain were countries connected to the So ...

. Likewise, the IRV set in ISO/IEC 646:1991 also changed the character back to a dollar sign.

KOI-7 N1

KOI-7 N1 (КОИ-7 Н1) was first standardized in GOST 13052-67, and later also in

ISO 5427 ISO 5427 is an 8-bit extension to the KOI-7 N1 character set, which was standardised by the ISO. The first half was published in 1979, and the second half was published in 1981. It supports the Russian Russian(s) may refer to: *Russians (), an ...

. It is sometimes referred to as "koi-0" as well. Compared to

ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...

and

uppercase and lowercase letters are swapped in order to make it easier to recognize Russian text when presented using ASCII. To trim the alphabet into chunks of 32 characters the dotted Ё/ë was dropped. In order to avoid conflicts with ASCII's and ISO 646's definition as

DEL Del, or nabla, is an operator used in mathematics (particularly in vector calculus) as a vector differential operator, usually represented by the nabla symbol ∇. When applied to a function defined on a one-dimensional domain, it denotes ...

and its usage as

EOF Eof (also Eoves) was a swineherd who claimed to have seen a vision of the Virgin Mary at Evesham in England, about 701. Eof related this vision to Egwin, Bishop of Worcester, who founded the great Evesham Abbey on the site of the apparition. '' ...

marker (-1) in some systems, it dropped the "CAPITAL HARD SIGN" Ъ that would have naturally resided at this location. In a Bulgarian variant the unnecessary Russian "CAPITAL YERY" Ы at code point 121 was replaced by the "CAPITAL HARD SIGN" Ъ.

KOI-7 N2

KOI-7 N2 (КОИ-7 Н2), like KOI-7 N1, was also standardized in GOST 13052-67. Kermit names it SHORT-KOI / short-koi.

KOI-7 N0

KOI-7 N1

KOI-7 N2

See also

References

Further reading