I'm not really wanting a keypad at this point (or is that can't afford one? - we just got through building our house). But, from what I understand, I could put just a "plain 'ol" x-10 switch in the 3rd box, and then all of the switches would work (PCS included)? And since I'm a newbie at electrical wiring, how can a multimeter help me determine what wires are going where? Thanks for your help!!!