I have been trying to create a digital output to trigger an external device with a TTL pulse. I have a Measurement Computing USB A/D board. I have only been able to pulse on the digital I/O lines with a very weak drive. Is there some other way to get a TTL pulse out? possibly the LPT port?
Which particular Measurement Computing model are you using? You mentioned an A/D board, but SuperLab supports only digital I/O, not analog.