Hmmmm....your mill has stepper motors, right? My notes on this are at work, but I seem to remember the following three Dyan-Mechtronics mills:
2200: Small benchtop, stepper motors
2400: upgraded 2200, built in oiler, stepper motors
2800: larger 'mid-size' unit, has an LED RPM display for spindle spindle motor has encoder, spindle has no reverse and can only be turned on/off by control cannot set speed via program, axis have stepper motors
Is that what your 2800 is like?