Power over Ethernet (POE) is a standard that allows Ethernet cables to transmit data and power simultaneously using a single network cable. This allows system integration and network installers to deploy powered devices in locations that lack electrical circuitry. POE lets network cables carry electrical power.
 

POE enabled cameras require only the network connection it will receive electrical power from this cable.

Benefits of POE

• Time and cost savings by reducing the time and expense of having electrical power cabling installed.

• Flexibility as devices such as IP cameras and wireless access points can be located wherever they are needed, and repositioned easily. 

• Safety in POE delivery as it's intelligent, and designed to protect network equipment from overload, underpowering, or incorrect installation.

• Reliable as power comes from a central and universally compatible source, rather than a collection of distributed wall adapters.  It can be backed up by an uninterruptible power supply, or controlled to easily disable or reset devices.