There is a much more complete character set translation library
The download to the files is on that page. But for convenience here it
There is a Ruby wrapper for the library here:
That particular page says the icu4r project is dead but it works fine
The real creator of this (as far as I can tell) is IBM. And, they know
a lot about the topic. The ICU stuff includes all the weird EBCDIC
pages which is what led me to find it.
It seems very complete and has more code pages than any other version of
iconv I’ve seen.