One of the limitations of PoE is that it is limited to a one hundred meter boundary. It is possible to use power over an Ethernet cable at distances exceeding one hundred meters but data transmission will often be corrupted. Phihong has developed two devices that will power up to four devices from a single Ethernet cable and extend the possibilities for PoE to two hundred meters. The indoor version may take its power from PoE or a separate AC adapter. The waterproof outdoor version may only be powered from PoE.