2013 Model. Upgrade all your intercom to this Advance 3 wire Plug & Play system. No more searching for AC outlets on the same phase of the wiring. This system bridges the two phases of the AC power-lines in the building and make them invisible. You don’t have to fumble for the right outlets to be on the same phase of the wire for the system to communicate. Since the system communicates by using the power-line in the building, no Radio Wave is involved, no worry for EMF danger. It is also free from concrete wall and metal construction material obstructions. Power-line Intercom System transmits wherever a wire in the building goes, up to 1500 feet in a straight line measure.