The pushbutton on the X10 wall switch controlling the fiercely incandescent lamp over the kitchen table has gotten erratic, so I dug into the Big Box o’ X10 Crap for a replacement. Turns out The Box has only 3-way switches, but the lamp needs a standard two-wire switch.
The instruction sheet shows this diagram:
The pushbutton on the CS277 “Companion” switch connects the red lead to the two blue leads. The blue leads are always connected together and carry the lamp current, so the red lead is just a signal from the remote button.
The WS477 “Master” switch will work as an ordinary switch if you cap the red lead with a wire nut and tuck it into the box.