submitted 1 week ago by Donatello@lemmy.ml to c/networking@sh.itjust.works

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Hi,

I have a IP camera that have two power input

a DC 12V and PoE

I've lost the 12V power supply.

So I'm considering to power it trough a simple PoE injector like those

I believe those do not come with a 802.3af negotiation protocol (Not sure) so if those injector directly inject the voltage. (Here 48v) will it work ?

Did you already tried ?

Sorry I know it's not "totally" network related but if you know where I can post I'm all ears.

Thanks.

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[-] tuff_wizard@aussie.zone 2 points 1 week ago* (last edited 1 week ago)

Pump the brakes. You need to find out what voltage it wants over PoE. There is NO guarantee that it is the same as the 12v input.

Standard Poe is like 48v. Unifi used 12v and 24v Poe for a while to power their antennas and AP’s but this is not standard and they have stopped doing it. This was supplied by their special poe injectors.

You will cause serious damage if you supply the wrong voltage to your device.

Edit: reread your post. The negotiation protocol is to

a. See if the device plugged into a Poe switch actually needs power

B. Negotiate higher supply’s like poe +, ++ and in future +++.

For a Simple PoE device the negotiation is not needed.

this post was submitted on 06 Oct 2025

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