CP866
From Just Solve the File Format Problem
Code Page 866 (CP866, DOS 866, DOS CP866, DOS Cyrillic Russian) is an 8-bit character encoding. It is a member of the family of MS-DOS encodings intended for use with languages using the Cyrillic alphabet, particularly Russian; it was more used in Russia than the other DOS Cyrillic encoding, CP855. The lower half is the same as CP437 (and ASCII). Its popularity in Russia was related to its having the full set of line and box drawing characters from CP437, as well as Cyrillic letters arranged in alphabetic order unlike KOI8-R.
