In one embodiment, a system may be provided that includes a circuit that is electrically coupled to a line. The circuit generates a direct current signal on the line, where the direct current signal has a period that includes a charge cycle and a discharge cycle. The circuit charges the line in the charge cycle and ceases to charge the line in the discharge cycle in order to generate the direct current signal. The line fails to fully discharge for at least a portion of the discharge cycle. To receive data from the line, the circuit detects a variation in a discharging of the line in the discharge cycle.