Turning Your Mac Into a Serial Console Server
chrisbw writes "Want to put that old VT100 terminal to use? Mac OS X Hits has a story on how to make a couple simple changes in OS X to enable login on a serial terminal (even over a USB serial adapter if you're on a newer mac). Cool trick for adding a text-based web surfing or email terminal in another room, or remote iTunes control!"
Well, my point was that if you're on a newer Mac that doesn't have a serial port, that you can use a USB serial adapter and OS X will happily use it as a regular tty.
Chris -- http://www.bitter.net/
This might answer your questions (look at section 6):
http://www.netbsd.org/
Short answer:
setenv input-device ttya
setenv output-device ttya