A circuit for stealing power from an external system without interfering with a communication protocol, the circuit comprising: a plurality of wiring connectors configured to receive a plurality of wires, wherein the plurality of wiring connectors are configured to receive a plurality of current levels set by the external system according to the communication protocol; a first voltage regulator configured to regulate a voltage on the plurality of wiring connectors at a plurality of voltage levels that are selected based on a transmit input sent over the plurality of wiring connectors according to the communication protocol; a current monitor (606, 814) configured to measure the plurality of current levels received through the plurality of wiring connectors and generate a digital signal proportional to a current received over the plurality of wiring connectors according to the communication protocol; a power converter; and a second voltage regulator connected to the power converter, the second voltage regulator configured to provide a current-limiting output, wherein the current-limiting output from the second voltage regulator drops in voltage when the second voltage regulator drops out, thereby causing the power converter to use less current, wherein the power converter is configured to optimize an amount of power stolen from the plurality of wiring connectors based on the current-limiting output, wherein optimizing the amount of power stolen comprises reducing an amount of power output by the power converter when the current-limiting output indicates that the second voltage regulator is dropping out and increasing an amount of power output by the power converter when the current-limiting output indicates that the second voltage regulator is not dropping out. a plurality of wiring connectors configured to receive a plurality of wires, wherein the plurality of wiring connectors are configured to receive a plurality of current levels set by the external system according to the communication protocol; a first voltage regulator configured to regulate a voltage on the plurality of wiring connectors at a plurality of voltage levels that are selected based on a transmit input sent over the plurality of wiring connectors according to the communication protocol; a current monitor (606, 814) configured to measure the plurality of current levels received through the plurality of wiring connectors and generate a digital signal proportional to a current received over the plurality of wiring connectors according to the communication protocol; a power converter; and a second voltage regulator connected to the power converter, the second voltage regulator configured to provide a current-limiting output, wherein the current-limiting output from the second voltage regulator drops in voltage when the second voltage regulator drops out, thereby causing the power converter to use less current, wherein the power converter is configured to optimize an amount of power stolen from the plurality of wiring connectors based on the current-limiting output, wherein optimizing the amount of power stolen comprises reducing an amount of power output by the power converter when the current-limiting output indicates that the second voltage regulator is dropping out and increasing an amount of power output by the power converter when the current-limiting output indicates that the second voltage regulator is not dropping out.