Several Cyrillic code-pages are widely used. Currently, LATEX contains support for 20 Cyrillic input encodings (some of which are variants of each other).
cp855 -- the standard MS-DOS Cyrillic code-page.
cp866 -- the standard MS-DOS Russian code-page.
Several code-pages very similar to this are also supported
(the differences are all in the range 242-254).
cp866av - the `Cyrillic Alternative' code-page (an
alternative variant of cp866);
cp866mav - the `Modified Alternative Variant';
cp866nav - the `New Alternative Variant';
cp866tat - an experimental Tatarian code-page.
cp1251 -- the standard MS Windows Cyrillic code-page.
cp866: there are several similar
code-pages which coincide for all Russian letters but add some other
Cyrillic letters. The following are supported:
isoir111 - the ISO-IR-111 ECMA Cyrillic Code Page.
iso88595 -- the ISO 8859-5 Cyrillic code-page (also called
ISO-IR-144).
maccyr -- the Apple Macintosh Cyrillic code-page (also known
as Microsoft cp10007) and macukr, the Apple Macintosh Ukrainian
code-page, very similar to the Cyrillic code-page.
ctt dbk mnk mos ncc mls.
These code-pages were taken from Oliver Corff's `MonTEX' package
(available at CTAN:language/mongolian/montex). Since the T2*
encodings support the Mongolian Cyrillic script, it is convenient to
have support for Mongolian input encodings as well. Pointers to
documentation for these code-pages will be much appreciated.