Communicating with PowerLab hardware: TTL

[mac]

Hi
My participants will be asked to complete an online survey with embedded film clips while psychophysiology recording is taking place concurrently.

I have read the TTL info in the MediaLab manual, and would like to be able to send info from MediaLab during my experiement to my PowerLab hardware or Chart software. But I can't figure out how to do this! I have attempted to use the IOTest.exe as recommended to test whether I can send signals, but when I do this, the only ports that come up say "Error". Do I need to set up ports somehow in advance?
I would appreciate any help with this, or advice RE the best way of sending signals between MediaLab and PowerLab.
Thanks.

[JEC]

Howdy,

I'd first point you to this thread in the MediaLab forum:

http://www.empirisoft.com/support/showthread.php?t=131

It's for an eye-tracking system, but the concepts are the same.

Which port are you trying to communicate through? Serial? Parallel? What address are you entering in the IOTest utility?

John