Are you a PoE user? Do you ever buy PoE equipment? If so, do you make sure it is compliant with the latest IEEE standard? If you just said yes to that last question, I want you to think about it again. How do you know if a part is really compliant to the IEEE Standard for Ethernet?
This topic came up during the last meeting of the IEEE802.3bt task force during a discussion of possible fault detection methods in a PSE. Unlike USB, where a compliance program was created by the USB Implementer’s Forum, there is no similar program for PoE equipment. In fact, anyone can put language in their data sheet, marketing information, or on their equipment that indicates compliance to the standard without anything to back it up. Some of these devices have no active components at all and simply inject power onto an Ethernet cable without any sort of detection or classification. Even worse, some of them do not even contain something to limit the current in the event of a fault.
Clearly, those of us who contribute to the standards process take compliance seriously and would like to see something done to limit the confusion. I believe an official compliance program would be best for both PoE suppliers and end users. By using an official logo like the USB compliance program, users would know immediately if a product had passed compliance testing. PoE suppliers would also be able go to a single place in order to verify that their parts work in the manner specified by the standard.
Now, there are a few things you can do to make sure you are getting legitimate PoE parts and equipment until a compliance program gets put together (if it happens at all). You can check to see if the part has been tested by the UNH Interoperability Lab. The UNH-IOL provides both conformance and interoperability testing for PoE equipment. In addition, SIFOS systems could be used to check the conformance of PoE parts and systems. However, the most important thing that you can do is to get your PoE equipment from a trusted source.
Are you in favor of an official compliance program for PoE? Would you be willing to pay a little more for a product with the official certification? Have you ever run across a product that states (or implies) that it is compliant to the standard when it is clearly not?
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Read all of my blogs here, and a few PoE-related resources:
- Application note - Implementing a 60-W End-to-End PoE System
- Download - PoE PD Efficiency Calculator tool
- System block diagram - Power-over-Ethernet (PoE)
- Power products - PoE Powered device (PD) products
- Power products - PoE Power sourcing equipment (PSE) products