I have a router made by Vision, with a Series II controller.  The controller as it sits now only accepts HPGL from a proprietary software supplied by Vision.  (I have it, but I don't like it - I want to do 3D work, so I'm attempting to retrofit it to work with Mach3.)
I've opened up the controller and isolated all the inputs / outputs that I need, except for the limit switches.  The steppers are driven by IM483 boards, which are quite well documented and I'm not finding many particular issues there.  I'll take STEP / DIR from each of the 4 to pins on a new DB25 connector that I'm adding to the housing, while leaving +5V connected to the existing controller.  I'm not bothering with a BOB here, as the drivers are fully opto-isolated, and they're still being powered by the PSU inside the controller.
Now the question I have about the drivers is the ENABLE pin.  It's currently being driven by the controller.  Should I leave it there, or connect it to the DB25 and drive it through Mach?  I'm guessing that this will kill the steppers when the E-stop is active?
Next question: the E-stop itself.  The controller has a 2-wire e-stop.  I'd like to keep it connected to the controller, as that will still be powering my spindle(s), dust collector, steppers, etc.    Can I simply take a tap off one leg of the e-stop wire (probably the black one) and run that to one of the input pins, and set that one as active-high in Mach3?  I guess the same question applies for the limit switches ...