How does Power over Ethernet work?

What is Power Over Ethernet? Power over Ethernet is a technology that lets network cables (cat5) carry electrical power, as well as data.

  • A typical cat5e cable for example, has 8 wires inside that flexible outter cable that you are pulling. 4 wires are used for data, leaving the other 4 wires for power.
  • When you install an access point outdoors, like the Ubiquiti Rocket M2 2.4 GHz MIMO Rocket AP, it requires a power and data connection.
  • Because the RocketM2 is POE-enabled, only the network connection needs to be made, as this access point will receive its electrical power from this cable as well.

What is a PoE Injector?

A POE Injector is used to add POE capability to regular non-POE network links. If you have an existing LAN, and want to add a outdoor access point, or IP security camera for example, a POE injector can be used. These are also called single port POE injectors, as they provide power + data to only 1 device.  These POE injectors have different power outputs, which depending on the device you are trying to power, will determine which POE to use.  For example, most residential grade access points, and routers will use a 12V, or 24V POE.  More commercial grade access points, and wireless Ethernet bridges, will use a 48V PoE Power Supply.

What is a PoE Ethernet Switch?

POE switch is a network switch that has Power over Ethernet injection built-in to some or all of its ports. It is basically a POE injector on each one of the POE enabled ports. This type of switch is useful when you are installing multiple access points that are POE-enabled, and do not want to add cludder to your power strip. To avoid using multiple POE injectors, a single POE switch will suffice.

What is the use of PoE?

Power over Ethernet brings many advantages to wireless network installations. Typically we are installing access points in the attic, on the roof, or up a pole, or tower. To prevent running both power and data lines concurrently, POE makes installations easy and more effecient by requiring only the cat5 cable. Typically maximum distance limitations are 300ft. or less.

Without requiring an electrical outlet next to every AP that is installed, POE makes installations flexible. We can install access points, and wireless bridge antennas virtually anywhere within 300ft. of a power outlet, or network switch.

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