On ISO 2022 compatible computer terminals KOI7-switched can be activated by the escape sequence ESC ( @ ESC ) N LS0.[2]
KOI-7 was used on machines like the SM EVM (СМ ЭВМ) and DVK (ДВК); KOI-7 N2 was utilized in the machine-language of the Elektronika D3-28[ru] as four-digit hexadecimal code, BESM-6, where it was called ВКД, (internal data code). The encodings were also used on RSX-11, RT-11 and similar systems.[4]
KOI-7 N0
KOI-7 N0[2] (КОИ-7 Н0[1]) is identical to the IRV set in ISO 646:1967.[2] Compared to US-ASCII, the dollar sign ("$") at code point 24 (hex) was replaced by the universal currency sign "¤", but this was not maintained in all cases, in particular not after the fall of the Iron Curtain. Likewise, the IRV set in ISO/IEC 646:1991 also changed the character back to a dollar sign.
KOI-7 N1 (КОИ-7 Н1[1]) was first standardized in GOST 13052-67,[5][6][7] and later also in ISO 5427.[2] It is sometimes referred to as "koi-0" as well.[6]
Compared to ASCII and ISO 646 uppercase and lowercase letters are swapped in order to make it easier to recognize Russian text when presented using ASCII.[6]
To trim the alphabet into chunks of 32 characters the dotted Ё/ë was dropped.[6] In order to avoid conflicts with ASCII's and ISO 646's definition as DEL and its usage as EOF marker (-1) in some systems, it dropped the "CAPITAL HARD SIGN" Ъ that would have naturally resided at this location.[6]
In a Bulgarian variant the unnecessary Russian "CAPITAL YERY" Ы at code point 121 was replaced by the "CAPITAL HARD SIGN" Ъ.[6]
12345Sokolov, Michael (2004-01-23). "Charset name: KOI7-switched". International Free Computing Task Force (IFCTF). Archived from the original on 2016-12-03. Retrieved 2016-12-02.
↑Freed, Ned; Dürst, Martin, eds. (2013-12-20). "Character Sets". RFC2978. Archived from the original on 2016-12-03. Retrieved 2016-12-03.
Kornai, Andras; Birnbaum, David J.; da Cruz, Frank; Davis, Bur; Fowler, George; Paine, Richard B.; Paperno, Slava; Simonsen, Keld J.; Thobe, Glenn E.; Vulis, Dimitri; van Wingen, Johan W. (1993-03-13). "CYRILLIC ENCODING FAQ Version 1.3". 1.3. Archived from the original on 2017-02-18. Retrieved 2020-06-24.
