Systems and methods convey information from a controller to at least one slave unit using a single wire referenced to an alternating current (AC) power supply. A control signal has a high voltage and a low voltage. The high voltage is greater than a voltage midpoint of the AC power supply and the low voltage is less than the voltage midpoint. The control signal is conveyed through the single wire to each of the at least one slave unit. At each slave unit, a comparison voltage, representative of the voltage midpoint, is generated by dividing substantially midway the potentials between the power lines of the AC power supply and the control signal is compared to the comparison voltage to determine low and high states of the control signal; the low and high states represent the information.