It was in September 2018 that the Institute of Electrical and Electronics Engineers (in English IEEE) officially launched the 802.3bt standard based on Power over Ethernet or PoE technology. This new standard allows the technology to go from a maximum power delivered until then from 30 Watts to 90 Watts.
It must be said that in about 16 years, since the ratification of the first PoE standard in 2003, there has been an increasing need for the power supply of computer network equipment. The observation is simple. Since 2003, the initial standard has undergone a great evolution, with a fairly significant extension of the technical characteristics, and the ratification of two standards for the same technology. First in 2009 with PoE + and in 2018 with 4PPoE.
Power over Ethernet is therefore of great interest to the Tech community. Let’s take stock of this very fashionable technology.
What is PoE?
Simply put, it will be said to be a technology for passing power through an Ethernet network cable. Thanks to Power over Ethernet technology, it is possible, in addition to data delivered at rates varying between 100 Mbps and 1 Gbps, to pass electric current under a voltage of 48 volts.
Of the 4 pairs contained in an STP or UTP type network cable, Power over Ethernet will allocate a few, at least two, for the transport of electrical energy. The primary objective of the development of this standard was to optimize the use of the Ethernet network cable and to bypass the installation of an additional electrical network to supply equipment, such as IP cameras, data points. Wifi access or terminals, network printers and IP telephones, in a computer network.
Power supply via Ethernet cable: advantages and uses
One of the interesting advantages of this technology is that it makes it possible to install IT equipment in locations where there is no power source or electrical outlets. Since data and electrical power will both pass through the same Ethernet cable, there is no need for a conventional power source or additional cable.
We can deduce that Power over Ethernet technology reduces costs, usage and the amount of cable to deploy, adapters of all kinds or connectors. This makes managing the network installation simpler and easier. These advantages have led to the use of the technology both at home in private homes and for professional uses in companies.
History of the standard: Power over Ethernet and PoE +
The first ratification of the Power over Ethernet standard was made in 2003 by the IEEE under the name 802.3af. This first standard was able to offer a power of 15.4 Watts. The deployment of 802.3af was planned on Ethernet networks of types 10 Base-T and 100 Base-T.
Faced with a fairly strong demand in the years that followed, the IEEE decided to develop PoE and began research in this direction in 2005. This work ended in 2009, with the publication of the standard. PoE + (discover our PoE + Panel PCs), better known by professionals as the 802.3at standard. Several changes are to be noted. Thanks to this new standard, the power delivered has practically doubled, going up to 30 Watts. The other major change is that the 802.3at standard is compatible with 1000 Base-T media.
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The announced powers of 15.3 Watts and 30 Watts respectively for the 802.3af and 802.3at standards, are those taken from the power source called PSE (for Power Source Equipment). The real power to be taken from the equipment and terminals is a little lower. So, because of the energy loss in the cable, we have about 13W and 26W for each of the technologies.
90W PoE or even Power over Ethernet to deliver 90w
Power reaching the 90 watts mark
After the success of the 802.3at standard, the Institute of Electrical and Electronics Engineers decided in 2013 to set up another research team, with the objective of approaching with Power over Ethernet technology, a power of 100W, in order to power more energy-intensive equipment. The 90W PoE or 4PPoE standard for 4-Pair Power over Ethernet, and better known by professionals as the IEEE P802.3bt standard, therefore saw the light of day a few years later. This is an extension of the PoE-Plus standard approved by the IEEE on September 27, 2018. This new extension of Power over Ethernet technology allows a category 4 computer network cable, a maximum theoretical power of 90 Watts for an intensity of 960mA per pair, ie six times the power of the initial standard. The loss during transport in the cable therefore makes 71W available at the level of the equipment connected via a category 4 cable. For a cat3 cable (category 3), we will have a power of 55W and a real power of 44W.
The major technical changes made
The first major change is the optimal use of cable. Instead of two pairs as is the case with the first two versions of the technology, the 90W PoE uses all four pairs. Another change is improving energy efficiency by reducing cable losses by half. The intensity is also more constant than with the previous two standards. When it comes to compatible cable types, 4PPoE can be deployed on 4 categories of cable. Requiring all pairs (i.e. four) for its operation, this new standard is compatible with type 1 GBase-T, 2.5 GBase-T, 5G Base-T and 10G Base-T links.
