The RCRP05B has 5 device buttons. Each button accepts a setup code, which is an index into a table of IR parameters. There are 4 tables- Cable/Satellite, TV, Video, and Audio. The DVD and DVR buttons both use the Video table. The instructions tell how to assign a setup code. Assign 2185 to the Cable button.
Cable 2185 had a set of parameters which is close to what you need to control the Dune (IR protocol and device/subdevice numbers), but it doesn't have the exact function numbers for the discrete power commands. Using the 994 command allows you to modify the function numbers.
Once you've assigned a EFC via 994 to a button, that assignment remains even if you were to change the setup code. If you're going to put the RCRP05B back in the drawer until you need to use it for some other learning exercise, or if you decide to use it as a everyday remote, it's quite possible to have forgotten that a couple of buttons are programmed to control the Dune. The you'll get frustrating results. So I recommend that you clear the assignment once you've finished teaching the Xsight 18. But of course it isn't necessary.
AR meant Acoustic Research.