My D180 only came with a couple resistors that are used to limit the voltage from the mag lead going to the tach input. The unit expects a > 10V pulse on the tach line, so analog tach senders won't work.
The current software allows a left and right input, and they can be set up as X pulses per rev to allow for differences in how the tach output is presented. For example, the pulse per rev setting is 1 for mags, and 2 for the Lightspeed (according to the LSE instructions). Best I can tell, the Dynon displays the first signal it sees, and ignores the other. When that signal is lost (during a mag check) it automatically switches to the other input.
Unfortunately, I just replaced my right mag with a Plasma-III, and have not been able to get the tach display to work. The LSE tach output is supposed to be 10V, and the Dynon wants "at least" 10V, so maybe it's close, but no cigar. I've got to put a scope on this and see what the voltage really is, but it's not my biggest problem at the moment.
Cheers,
Rusty (nearly free)