Described herein is a data communication system using power over Ethernet (PoE) for power distribution, comprising a first and second powered device (PD), each of which is adapted to communicate with each other through an Ethernet data path (EDP) and is further adapted to receive direct current (DC) power using a PoE protocol, and a mid-span power injection device (MSPID) adapted to provide a communications interface such that data communications passes through the MSPID to and from each of the PDs, and wherein the MSPID is further adapted to provide a first DC power to only the first PD using the EDP, and to provide a second DC power to only the second PD using the EDP.