Sorry, but being a newbie to this stuff I don’t understand. I have no idea what protocol the RealSimGear unit or my 2560 connected via SimVim uses. All I know is that the RealSim Gear GPS gets assigned to a COM port in Windows 10 as an Arduino Mega 2560. When I connect my separate 2560 using SimVim it takes control of that COM port. Additional information that might help is that when I updated the firmware for the GPS it didn’t work at first. The tech then suggested I plug the USB cable into another port. That fixed it. The unit came online and was assigned to COM3.