Actually what you want to do is what these units are designed to do and are quite easy to program once you understand the basics. I suggest you download and peruse the MX-700 tutorial from the files section of this forum as a start; same programming techniques as your MX-850. Also in the files section you will find many mxf & mxd files of systems/devices programmed by others and submitted to the forum for use by the members. Good luck & enjoy.