Can the XTB-II/R be plugged into an ordinary 120V outlet?
Yes it can. Just connect a standard power cord to “120V PHASE I PWR” and “NEUTRAL” on J2. A good tuned-circuit phase coupler is still required near the distribution panel if X10 devices are used on both phases. The closer the XTB-II/R is to the distribution panel, the stronger the signals will be throughout your home.