User`s manual

TransType Pro
56
Reencoding
Type 1 fonts also must be reencoded when converting from PC to
Macintosh. To simplify this process and make it similar to the one used
when TrueType fonts are processed, TransType automatically assigns
Unicode indexes to all characters in a Type 1 font using a special table
containing thousands of name-Unicode pairs. This way TransType can
correctly handle Type 1 fonts that have more than 256 characters.
Note that this name->Unicode method works correctly only when
characters in a Type 1 font have correct PostScript names. In cases when
names are assigned incorrectly (for example, characters from a non-Latin
language using Latin character names) another method is used, similar to
the one that we described above when talking about the conversion of
symbol-encoded TrueType fonts.