Power-over-ethernet to non-PoE device

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While I can find lots of information about PoE, I'm finding little about "gotchas" or "warnings".

That being said, what would happen if I configured a switch to give PoE then plugged that into a device that doesn't support PoE? Would it damage the endpoint device?

user356950

Posted 2014-08-21T17:23:02.033

Reputation: 313

Question was closed 2014-08-21T18:19:53.580

I can say from experience, all of our corporate data center switches are configured for PoE for our phones, but we can safely plug those network cables into any other device as well. Laptops, Desktops, dumb switches etc. Hopefully someone can explain the science of it in the answers. – Callen L – 2014-08-21T17:28:10.457

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possible duplicate of Can I connect a PC to a PoE switch?, Is it harmful to plug a POE energized data source into non-POE NIC card?

– Ƭᴇcʜιᴇ007 – 2014-08-21T17:29:40.033

Answers

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No, you won't damage those devices. There are occasional posts to the contrary online but for the most part it seems that PoE is only activated after an initialization request is sent. A better discussion can be found here: http://community.spiceworks.com/topic/187505-mixing-poe-and-non-poe-devices

PoE Detection occurs like this "In order to avoid damage to non-PoE devices, a key component of the 802.3af PoE standard is detection. PSEs must be able to detect the presence of a PoE-enabled device before sending power, and must be able to detect when the powered device is no longer present and remove power. To achieve accurate detection, a low-level detection current is sent from the PSE through the cable and the response is analyzed to determine if a compliant device is attached."

The rest of the explanation of PoE and the standard can be found here: http://www.network-1.com/poe/poe_ovw.htm

Abraxas

Posted 2014-08-21T17:23:02.033

Reputation: 3 704