Patent ID: 8767867

Claim:
A method comprising: controlling a switching frequency of a switched-mode power supply unit (PSU) to operate at a first frequency in a non-communication mode; and modulating the switching frequency of the switched-mode PSU between a plurality of spread frequencies to transmit data on a power line coupled to the switched-mode PSU in a data-transmitting mode, wherein the modulating comprises: modulating the switched-mode PSU with a first value when in the non-communication mode, wherein the first value corresponds to the first frequency; modulating the switch-mode PSU with a second value to transmit a 0 bit in the transmit data when in the data-transmitting mode, wherein the second value corresponds to a second frequency of the plurality of spread frequencies; and modulating the switched-mode PSU with a third value to transmit a 1 bit in the transmit data when in the data-transmitting mode, wherein the third value corresponds to a third frequency of the plurality of spread frequencies.