What’s the Difference Between PoE and PoE+?

Original Post - Press Office, VersaLogic Corporation, 12/03/20


The team at VersaLogic are constantly pushing boundaries and exploring new technology. Its one of the many reasons we enjoy working with them.

In December they published a detailed blog post providing an overview of PoE (Power over Ethernet), and the difference between PoE and PoE+. It explains power sourcing and the various ways that devices in the system can be powered. The original blog post goes into much more detail, you can read it here.

PoE, short for Power over Ethernet, is a way of powering peripheral devices, such as cameras or wireless access points, without the need for a separate power cable or local power source. All of the power needed to operate the device is provided over the standard Ethernet cable.

PoE comes in a variety of flavors and the related standards have been developed within the overall remit of the IEEE 802.3 Ethernet Working Group. The original definition of PoE envisaged the Power Sourcing Equipment (PSE) would deliver 15.4W and, after line drops, 12.95 W would be available to the Powered Device (PD). PoE+ takes this up to 30W from the PSE with 25.5W available at the PD. Higher levels are also possible with PoE++ which specifies up to 100W at the PSE.

The terms PoE and PoE+ are widely used, but the terms Type 1 (PoE) and Type 2 (PoE+) are also used. In addition, there are also 5 defined power classes. During power-up, the PSE determines the power classification of the PD. To avoid damage to non-PoE enabled devices, the PSE will only supply power to PoE enabled devices.

There are many types of PDs such as cameras, wireless access points, VOIP phones, light fixtures, and sensors. Their need for PoE versus POE+ is based strictly on their total power requirements (either above or below 12.95W).

Whether a wireless access point requires a PoE or PoE+ may depend on the environmental conditions. When operating in environments of > -20°C, PoE power is sufficient. However, when the temperature plummets into the range -50° to -20°C an internal heater is required, driving the need for PoE+ power.

Industrial / embedded computers may have PoE ports built-in, or they can often use some type of PoE expansion board. VersaLogic’s “Grizzly” computer board is an example of a high-performance system that includes built-in PoE ports.

For a deeper dive into PoE, Microsemi has a white paper that provides more detail. If you'd like to know more about VersaLogic’s range of products with PoE options please get in touch with one of our knowledgeable engineers.

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