I lost my sanity last weekend with this same issue... a Motorola DVR. I was able to get the mx-3000 to work with sending IR commands... but then RF (being fed through a msc-400 was doing nothing with it's IR emitter). I sat around and messed with the strength of the IR output, differnet placement, etc.... still nothing. Long story short, for some reason the IR emitter from URC is not compatible with some Motorola DVR's (and I tried about 10 brand new URC emitters just to be sure). I had a bunch of different brand emitters laying around... I plugged one in that wasnt from URC.... and bam, worked immediately and flawlessly. I think that the IR emitter i used was from a Next Generation Remote Extender. Hope it helps :)