Ever felt discouraged when looking at a bunch of electrical wires, all tangled up, not knowing which one is the one you are looking for? Things have gotten significantly better though, with the rollout of the PoE technology in recent years. Power over Ethernet (PoE) refers to this idea that ethernet cables can now simultaneously deliver data AND power to a device. “One cable to rule them all”, PoE opens up new perspectives for telecom players.

What is PoE? 

A formal definition would describe Power over Ethernet as the standard that enables ethernet cables to transmit data and power via a single network cable. To better grasp why it is such an improvement though, it is useful to start by analyzing the traditional connection setup for a communicating device. We differentiate the device that receives the power from the network cable (PD: Powered Device; an IP camera, a router) and the device whose job is to make the power available in the cable (PSE: Power Sourcing Equipment). 

PoE connection

As illustrated above, a PD requires both electrical power and data connection to function. Two cables then, serving two different purposes.  

On the other hand, PoE merges these two cables into a single one. The PD still needs electrical power and data, but it gets them through a single cable. 

What are the advantages?

The main advantage of PoE therefore becomes obvious: cost savings. Fewer cables to be installed makes the wallet happier, especially when, due to a remote location or specific constraints, a certified electrician’s intervention would have been necessary. 

Then PoE offers telecom operators more flexibility. It makes it easier to add new equipment to the network. Indeed, electric cables sometimes have to be buried or armored whereas PoE’s “plug-and-play” approach saves a lot of troubles to network engineers. In addition, PoE is key for the deployment of telecom devices in outdoor locations

One benefit that should also not be overlooked is the increase in safety. Not relying on electric cables any longer accordingly means that power outages are less of a concern than before. If the PSE is up and running, no matter what might happen on the grid, your powered device will still be on. Plus, PoE switches are often coupled with redundant safety mechanisms.

Do I need special wiring?

No! Regular ethernet cables (from cat5 to cat7A) are up to the task. 

Two different ways to organize PoE within an ethernet cable.

Every ethernet cable consists of four pairs of wires. Usually, two are dedicated to data transportation and the other two are ‘spare’ wires, which can therefore be used to carry electrical power. It is also possible for the data signal and the electrical power to travel through the same pair of wires since they are both at the opposite end of the frequency spectrum and thus risk no interferences. 

Can I power any device using PoE?

To answer this question, it must be said that several PoE standards exist. As the years went by, PoE technology has been refined and the most recent standards can now supply significant amounts of power. While a regular VoIP phone can be powered with the most basic PoE standard, a computer will require you to go for a more advanced one.

PoE standards comparison

Characteristics802.3af Type 1 ' PoE '802.3at Type 2 'PoE+'802.3bt Type 3 '4PPoE'802.3bt Type 4
Power available for PD
Power delivered by PSE15.40W30W60W100W
Voltage range at PSE44-57V50-57V50-57V52-57V
Voltage range at PD37-57V42.5-57V42.5-57V41.1-57V

How expensive it is?

As stated before, PoE mostly relies on already existing ethernet equipment. It does not require you to turn your network architecture upside down either. At most, a PoE Midspan injector has to be inserted between a regular network switch and a powered device to enable PoE. Even so, existing connections remain untouched and no further adaptations are required since the switch and the PoE injector can communicate between themselves.

Concluding remarks

Power of Ethernet is a smart technological leap forward – for once, it actually simplifies things rather than adding a new layer of complexity! For telecom operators, it represents an economical and safe way to expand their network. In fact, PoE resonates very well with the new trend in telecom networks – small outdoor radio access points – and odds are that it will be increasingly used. 

Yet again, even the most amazing technology innovation is useless if not properly powered. Autonom’s mission is to make sure your network is always up and running, even in the event of a power outage. To that end, Autonm has designed his brand new AutoPoE, a PoE injector that comes with a smart battery. Fancy a look? Click right here!

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