The 15-2117 does send X-10 codes via RF to its base station. The problem is that the base station doesn't have a data interface to the AC line, so the X-10 codes go nowhere except out of its IR emitter. (I have the same problem with the 15-1925 base station.) The IR to X-10 box is your only choice, whether it's the IR543 or the base station for the 15-1919 remote control which does have the interface, but may not be on the same RF channel as the 15-2117. (My 15-1925 won't talk to my 15-1919 base station via RF.)