With this Extender you can use up to 70m of high quality inexpensive Cat.5e/6 cable to connect a DVI source to a DVI display device. The slim RJ45 connectors and Cat.6 cable (not included) allow greater flexibility not possible with larger DVI connectors and cables. Normal operation will not require external power; however the Transmitter unit allows external power to be attached in cases where the graphics card does not provide sufficient power, either using a USB Micro-B Cable or an external power supply connected to the supplied USB to DC cable.