I'm confused where to go from here with CMD-260 and NEMA 42

I've got a Bridgeport Milling machine with an obsolete NC controller
from a manufacturer who is out of business and on whom I have no
documentation. It used an Ecco paper tape drive to a DB-25, but
without knowing what language it used to talk to the controller, (or
even if the port is a serial or a parallel), I figure, I might as
well keep the power supply and replace the rest with more modern
stepper drives. The X, Y and Z axis are fitted with (direct coupled)
8 wire connected NEMA 42 steppers (which I believe are Superior
Electric from about 1975 or 1980). The motors do not have name
plates (why make my life easy?).

I just bought three CMD-260 drives on E-Bay (which I think were from
someone who bought them from Tim Goldstein). I bought them instead
of Gecko 210's because they were rated at a higher amperage which I
thought might be needed for the NEMA 42 steppers. I also bought an
Axxus Technologies DB1V2.0 CNC Parallel Port Interface which I
thought would be helpful. I also intend to buy some heat sinks and
fans for the drives.

OK, now the question: Has anyone got a clue what voltage and current
setting to put the drives and power supply at? I can probably test
the existing power supply for D.C. voltage. Can I use this reading
and the coil resistance of the motor to figure out the amperage
setting? Is there another way to identify the motor specifications
and requirements?

Any assistance would be appreciated in what the motors are likely to
be, and any hints to make my life less exciting when I put the
assorted gadgets together.

Thanks in advance,
Jeff Goldberg