Abstract: Apparatuses are provided for adapting USB, Thunderbolt, and similar connections to an Ethernet connection with dynamic multiplex power supply. The apparatuses of this disclosure are adapted to connect and power a peripheral device via its Ethernet port from a USB, Thunderbolt, or similar connection of a host computer. A power multiplexer is utilized in conjunction with a current detection circuitry and a PoE enable logic block to provide and regulate dynamic multiplex power supply from a multiplicity of power sources including an external direct current and a USB or Thunderbolt connection from a host computer.