In an embodiment, an apparatus includes a source device including a first current limiter and a second current limiter in parallel with each other and a first transformer and a second transformer; a load device includes a third transformer and a fourth transformer in parallel with each other; and an Ethernet cable is electrically coupled between the source device and the load device, the Ethernet cable including first twisted pair lines and second twisted pair lines. A direct current (DC) voltage is provided to the first current limiter and the second current limiter, the first transformer is electrically coupled to an output of the first current limiter, and the second transformer is electrically coupled to an output of the second current limiter. The DC voltage is transmitted to the third transformer and the fourth transformer in parallel with each other via the first twisted pair lines and the second twisted pair lines. The first twisted pair lines and second twisted pair lines are included in an Ethernet cable electrically coupled between the source device and the load device.