It's probably not important which piece of hardware you connect the MediaLab computer to. If it were me, I'd start with the 'event' input you've mentioned below.

It's a fairly simple matter to make a new cable to connect the two systems.

You'll need two wires: one which connects MediaLab's 'D0' pin to the 'event' input on your hardware, and one which connects ground between the two systems.

Take a look at this forum posting:

http://www.empirisoft.com/support/showthread.php?t=762

The idea is the same. However, instead of connecting to 'nACK' on the second machine, you'll want to connect to the event input of your outboard hardware.

It's probably a two minute job with a soldering iron and multimeter, if you have those things available.

Does that help?

John