Power over Ethernet technology allows ordinary Ethernet cables to act as power cords. In a PoE-enabled network, DC flows over the network cable along with normal Ethernet data traffic. This allows a single cable to provide both data connection and power to devices such as wireless access points, IP cameras, and VoIP phones.
To carry the power over this Ethernet data cables, certain IEEE standards are defined. These standards define properties of the established link, what is the maximum DC power which can be safely transferred over the network cables, what is the range of DC voltage, what should be the cable resistance, what is the allowable maximum current over the link
IEEE 802.3 af – Provides up to 15.4 W of DC power on each port
IEEE 802.3 at – Provides up to 25.5 W of power for “”Type 2” devices
IEEE 802.3 Bt – Provides up to 55 W for “Type 3” and up to 90-100 W for “Type 4” devices.
The advantage of PoE is that installation of Ethernet connected devices to the inaccessible locations where it is difficult to provide power supply or where too many cables are in the way. Also, there is no need for the separate cable for the powering up the devices. So, using PoE it is possible to maximize the savings on the installation cost.
Benefits of PoE:
PoE benefits organizations in many ways. Reduced installation costs, safety, responsive deployments, data-gathering capabilities, and productivity enhancements. End users can plug PoE devices into existing networks or start from scratch with ease.