Ned -
As far as I can tell, the pedigree of 2022-JP is that this is what was
implemented by Japanese terminal manufacturers for use on 7-bit links. Hence,
it is not an `informal' standard. Rather, it was the only valid way to
transmit JIS -- which is a recognized standard -- over 7-bit. The JUNET
requirements for use of 2022-JP naturally gravitated to that given the fact
that RFC-822/SMTP mail is fundamentally 7-bit. JIS is a 14-bit character set.
If you support ASCII -- and Japanese terminals do -- then the only way you
have to go between JIS and ASCII is either to use the 8th bit as a JIS flag or
to have a shifting sequence.
In other words, I believe that Japanese kanji terminals preceeded JUNET
requirements. It isn't that JUNET people specified this; rather, they
specified 7-bits and here's how it's done.
I don't mind 2022-JP being in a separate document, as long as the name is
still specified and blessed in XXXX so we can use it now instead of waiting
for JUNET to (1) become aware of the need to write the document (2) to produce
a suitably formal document (3) get it through the Internet standardization
process.
-- Mark --