What is Power over Ethernet?

Power over Ethernet (POE) is a technology that lets network cables carry electrical power.

For example, a digital security camera normally requires two connections to be made when it is installed:

A network connection, in order to be able to communicate with video recording and display equipment

A power connection, to deliver the electrical power the camera needs to operate

However, if the camera is POE-enabled, only the network connection needs to be made, as it will receive its electrical power from this cable as well.

Power over Ethernet reduces the number of cables required to connect a POE IP camera

Why use POE?

Specifying Power over Ethernet brings many advantages to an installation:

Time and cost savings – by reducing the time and expense of having electrical power cabling installed.  Network cables do not require a qualified electrician to fit them, and can be located anywhere.

Flexibility – without being tethered to an electrical outlet, devices such as IP cameras and wireless access points can be located wherever they are needed most, and repositioned easily if required.

Safety – POE delivery is intelligent, and designed to protect network equipment from overload, underpowering, or incorrect installation.

Reliability – POE 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.

Scalability – having power available on the network means that installation and distribution of network connections is simple and effective.

Devices that use Power over Ethernet

POE has many applications, but the three key areas are:

VoIP phones – the original POE application.  Using POE means phones have a single connection to a wall socket, and can be remotely powered down, just like with the older analog systems.

IP cameras – POE is now ubiquitous on networked surveillance cameras, where it enables fast deployment and easy repositioning.

Wireless – Wifi and Bluetooth APs and RFID readers are commonly PoE-compatible, to allow remote location away from AC outlets, and relocation following site surveys.