man mount, after searching for the string "Mount options for fat":
codepage=value
Sets the codepage for converting to shortname characters on FAT and VFAT
filesystems. By default, codepage 437 is used.
iocharset=value
Character set to use for converting between 8 bit characters and 16 bit Unicode
characters. The default is iso8859-1. Long filenames are stored on disk in Uni-
code format.