After much deliberation, I've come to the conclusion that the easiest way for me to control 3 mac 500e's from on stage is to use my laptop with some sort of dongle to output DMX. I'm giving a workshop on moving lights, and I'm currently stranded in red deer. I highly douby my ability to make it into a major city to find a dongle that will do what I want it to, and even if I do I'm not sure I want to pay the price. I'm looking primarily at the Win Commander style dongle from Audio Visual Lighting (http://www.xs4all.be/avl/wincommander.htm) since it seems to lack any extra electronics and is straight from printer port. This makes life easy for me, it's just a matter of figuring out what pins on the printer port provide the 3 DMX lines I need. I've started searching for a DIY project on the net, but haven't had too much luck so far. If anyone has accomplished something like this or knows of a good resource that would assist me in making one, I would love to hear about it! Thanks in advance.