I tried the "optical" approach (i.e. I connected an IR emitter to the IR output of the RFX9600 and placed it in front of an IR receiver connected to my Xantech 791-44 connecting block). This "optical" approach works well. My X10 and TiVo commands work correctly. With the other approach (which was connecting a 3.5mm cable to the IR output of the RFX9600 and connecting the other end of the cable directly to the Xantech 791-44), the X10 and TiVo commands would not work correctly. The interesting thing is that, with this direct wire approach, other devices, such as my Denon DVD-3910 DVD player, a Toshiba HD-A3 HD DVD player, and an ancient VCR (which I use maybe once a year) worked correctly. It's just that the X10 and TiVo didn't work. Anyway, I'm using the optical approach and everything works fine now! Thanks, Barry!