Hi,
I am hoping that someone has the knowledge to help me. 

I have an IAT set up, however I would like to record heart rate and skin responses via a biopac. The biopac and inquisit are currently on two different computers, and would need a lead to connect them. Would I need to connect the response pad to the biopac, or would I need to code it in inquisit? I would like the response pad to trigger the biopac to put a marker on it, as I would like the response recorded for the stimuli.

Thank you 

You would connect the two computers via their respective parallel ports. You would then add a <port> element to the IAT script and use the <trial>'s /responsemessage attribute to "send" the TTL signal upon response.

https://www.millisecond.com/forums/FindPost1740.aspx

You would conversely set up the biopac system to register that TTL marker.