Are you using an emitter on the front of the cable box? Have you tried placement of the emitter in different locations? What is the model of the cable box? Have you tried the 'low' setting for the emitter coming off the RFX9400? The reason I ask is due to the older motorola cable boxes did not like the 'hot' signal that used to come from RFX6000/6500 for Classic and NG Prontos.

In fact, if you want more info on that, search Classic Pronto forum for +black +electrical +tape +pinhole and I'm thinking you will find some hits.

Of course, the questions above are still relevant. I must put in the newer 3300 box (no DVR or digit display, just black box) into my bedroom and had to stick an emitter on the front in the middle of the unit to get the thing to work.

I was NOT able to use the wired IR jack on the back of the unit as I could not figure out the correct pinout to get things to work properly.