My old remote for the 721 gave up the ghost and I purchased a new one on eBay. What I got was a 6.0. It has a green (1) and a blue (2) tab. Neither of these will let it control the 721. I read someplace that the green tab is for IR only and the blue tab is for IR/UHF and that a black tab is required to let this remote control the 721. Is there some way to modify the existing tab so that I can use this remote?