In this article:
- What is Power over Ethernet?
- Why use PoE?
- Which Devices Use Power over Ethernet?
- How to upgrade to PoE
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 usually 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.
Why use PoE?
Specifying Power over Ethernet brings many advantages to an installation:
- Time and cost savings - by reducing the time and expense of electrical power cable installation. Network cables do not require a qualified electrician to fit them and located anywhere.
- Flexibility - without being tethered to an electrical outlet, devices such as IP cameras and wireless access points can be wherever they are needed most and repositioned if required.
- Safety - PoE delivery protects 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 disable or reset devices.
- Scalability - having power available on the network means that installation and distribution of network connections is simple and effective.
Which Devices Use Power over Ethernet?
PoE has many applications, but the three key areas are:
- VoIP (Voice over Internet Protocol) 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 analogue systems.
- IP cameras - PoE is now ubiquitous on networked surveillance cameras, enabling fast deployment and easy repositioning.
- Wireless - Wifi and Bluetooth APs and RFID readers are commonly PoE-compatible allowing remote location away from AC outlets and relocation following site surveys.
How to upgrade to PoE
Adding PoE to your network is straightforward and there are two routes you can choose:
A PoE switch is a network switch with Power over Ethernet injection built-in. By connecting other network devices to the PoE switch it will detect whether they are PoE-compatible and enable power automatically.
PoE switches are available to suit all applications, from low-cost unmanaged edge switches with a few ports, to complex multi-port rack-mounted units with sophisticated management.
A midspan (or PoE injector) adds PoE capability to regular non-PoE network links. Midspans can upgrade existing LAN installations to PoE and provide a versatile solution where fewer PoE ports are required.
Upgrading each network connection to PoE is as simple as patching it through the midspan with power injection controlled and automatic.
Midspans are available as multi-port rack-mounted units or low-cost single-port injectors.
It is also possible to upgrade powered devices, such as IP cameras, to PoE using a PoE splitter.
The PoE splitter is patched in to the camera’s network connection and taps off the PoE power, converting it into a lower voltage suitable for the camera.