Code pages for Cyrillic

[Robert]

Dear SEELANGers,

I have been looking for information on code page 855 ("IBM
Cyrillic"?) for DOS.  It seems most people are familiar with
code page 866, but a text-to-speech software package I am
interested in for Cyrillic characters seems to be using only
code page 855.  Does anybody whether or not code page 855 is the
same as code page 866 or could it be somehow converted into 866
or converted into 866?

Many thanks,

Robert Greenberg
greenberg at unc.edu