Dmc I believe is a type of 485 but I think it's modified, ie there's 24v power on some of the pins. Do you not have a laptop to connect to these? You can get the orange adapter cable for dmcs from vertical express.
If you are trying to do something else get a 2 channel scope and you can see what protocol its using by comparing the waveforms against known protocols. If you are please do tell. The days of folks doing that sort of stuff to that age of equipment I thought was behind us. Most folks hear mph or 300a and the only thing they want to do is rip it out and replace it. Im in that camp too honestly. DMCs are good though...
