EMC questions

Hi,
I'm unclear about how EMC drives a open loop step/dir interface.
Is there an open loop configuration or does it just dummy out the
feedback loop in software?
So I thought I would just try installing it and see what happens,
but the BDI install isn't detecting my monitor type. It's asking for
the nearest type, or else to enter the horizontal and vertical
refresh rates, as if I would know. Does anyone know of a safe choice
to enter here ? Thanks for any hints.

Rob