Simplex’s original sync strobes flashed every time power was cut to the strobe. The NAC would have to be set to “pulse” (60 bpm march time) for them to work properly.
Are the newer SmartSync strobes compatible with (i.e. could they serve as a replacement for) the older sync strobes?
I know the older ones can work with the newer sync modules that work with newer strobes. It would be a safe bet that the old one can be replaced with the new one.
I believe other people have managed to get theirs to work by setting the signal circuit they put the strobe on to Slow March Time (60bpm) as well. If your MDL can pulse at 60bpm, you should be just fine. Out of curiosity, do you have a panel?