Sending data to Mac II ports on a MacIvory

[Rodney Daughtrey <bcsaic!huntsai!rodney@BEAVER.CS.WASHINGTON.EDU>]

I'm building an interactive music composition tool on the
Symbolics (as part of my master's thesis), and I'd like to
allow the program to drive a MIDI-equipped keyboard when
performing compositions on a MacIvory.  To do this, I need
to know how to send bytes (from LISP) to either the printer
or modem ports on the Mac II.  Knowing nothing about the
Mac internals/toolbox calls, what's the best/easiest way to
do this?

Thanks in advance,
Rodney Daughtrey