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I know the concept of how PoE works


G+_Jason Perry
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I know the concept of how PoE works.

I know how to make a DIY PoE cable.

 

Does anyone know where online to look to find out the details of how an actual PoE connection is set up? If I look on the IEEE website you have to pay to download the spec. I don't need to run 48V into one of my projects. We all know what happens when Cranky Hippo.... I mean someone runs too many volts into a project.

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POE devices are typically between 18 and 48 volts, recently most have moved to 48v to be standardized. I have seen standard POE injectors in 24, 30 and 48v options but many switching devices have POE built in now. However, if these carry a voltage higher than the end device requires I would suggest making your own custom POE injector; if you have a single application that is.

 

You can easily make a custom POE injector for the device using this wiring below. Here is a web page that shows the custom creation process.

 

http://blog.undr.com/2010/04/make-your-own-power-over-ethernet-injector/

 

My Ubiquiti Edge Max router accepts up to 24v on the POE Input, it does not provide POE power on its own; besides the power supply for the Ubiquiti is only 12v @.5 amps so it would not drive much.

 

22994%20-%20POEWiring.png

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I use a pair of Passive Injector-Splitter adapters for each of my Security IP Cams. I "inject" the camera power supply (12V, 1A) at the beginning of the Ethernet cable that runs to an IP Cam. I do this using one of the pair of Passive Injector-Splitter adapters which matches the camera "wall wart" power plug. I then run a Ethernet cable from the Injector to a IP Camera (this Ethernet cable is now carrying both the network signal and the desired IP Camera power).

 

I install the Ethernet cable (which is powered/supplied by/from the "Injector") to the desired IP Camera. I attach a corresponding Passive "Splitter" to the end of that Ethernet cable. The "Splitter" provides both the Ethernet plug as well as the IP Camera barrel connector. The male barrel connector is the corresponding "mate" to the IP Camera female barrel connector. (in my case a 5.5mm x 2.1mm barrel plug)

 

Here is a link to one type of Passive "Injector-Splitter" which I use. I have tried several and have had good reliable experience with these. 8PCS POE Passive Cable CCTV Power Over Ethernet POE Injector Splitter Adapter:

 

ebay.com - Details about 8PCS POE Passive Cable CCTV Power Over Ethernet POE Injector Splitter Adapter

 

If you look at that link and scroll down tot he detailed description you will find more information that may help to explain what I have attempted to state above.

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