I had a quick look at it. The reason it works with X-Plane and not DCS are the way the developer have chosen to grab the information from X-Plane, namely from the "Data Input & Output" / "Data Set". That delivers data in I think CSV format for general usage. DCS-to-GPS requires the format to be in either NMEA or AHRS format. If the developer had chosen to grab the X-Plane information via one of the AHRS export options instead, it would have worked with DCS-to-GPS as well. I'm guessing he made his choice based on wanting to have access to aircraft systems like the pitot static system (pressures), for whatever reason. Maybe I could implement a way to export DCS information in the way A-EFIS requires, but to be perfectly honest with you I don't believe I have the time to spare, and at the time being I don't fly much myself at all either. But maybe, in a not foreseeable future, I might give it a try just for the challenge. In that case you hear about it here.