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kd7vea
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Dual voltage POE on CRS112-8P-4S-IN

Wed Aug 01, 2018 10:55 pm

I am looking at getting a CRS112-8P-4S-IN, and I cant find the answer to this anywhere. If I use the "POE IN" at 48 volts from a switch with active POE will that also let me power devices at 24 volts, or will I need a seperate power supply to do that? I have a bunch of Ubiquity Gear that needs 24 volts I want to feed at the top of a tower, but I already have a 48 volt Cat6 cable at the bottom, Will this work?
 
mistry7
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Re: Dual voltage POE on CRS112-8P-4S-IN  [SOLVED]

Thu Aug 02, 2018 12:27 am

No you need both voltages from 2 different power supply’s
 
jo2jo
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Re: Dual voltage POE on CRS112-8P-4S-IN

Thu May 16, 2019 2:23 am

what im still not 100% clear on, is assuming you have 2x Power supplies connected to a CRS112-8P-4S (a 48v one and a 24v one), are you then able to power eth connected devices at BOTH 48v (active POE) *AND* devices at 24v (passive poe)?

ie: could i connect a IP Camera (802.3af Active POE) to eth3 , AND then a mikrotik RB433 (24v Passive POE) to eth6?
(is there an option in winbox on the int->eth->poe tab that lets you choose each eth ports output?)

Or is it ALL eth ports must be 48v OR all eth ports must be 24v?

For example you can do this on Ubiquiti EdgeSwitches (manually via the gui, you can set *each* eth port, individually, to output either: 24v Passive, 48v Active (poe "AF"), or 48v Active (poe+)

thanks
:beep :beep :beep
 
jo2jo
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Re: Dual voltage POE on CRS112-8P-4S-IN

Tue May 21, 2019 7:34 am

well ill have one of these units here in a day or two, and will test exactly what my question/reply above states. Ill update here when i know.

It would be really nice!, if you are able to power a 24v passive poe device on eth3 , and a active ~48v af/at poe device (ie a IPcam) on eth5 , at the same time (like you can on ubnt edgeswitches)
:beep :beep :beep
 
jo2jo
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Re: Dual voltage POE on CRS112-8P-4S-IN

Wed May 22, 2019 9:14 pm

great news / great solution to this question that ive been having for over 6 months (ever since that first announcement PDF mt news-letter)! it looks like you CAN run a 24v passive device AND a 48v active poe device from these crs112-8p MTs at the same time!

there is exactly what i was hoping for, an option in winbox -> eth -> poe tab , where you can set PoE voltage = High/Low. (see img)

ofcourse you need to provide the MT with 24v and 48v psus at the same time, but this is great news / great use case for these units!

I have read the PDF manual and sales pages, and every forum post i could find on this unit, and none of them 100% clearly (IMO) state that this is possible, they do hint at it, but to me, it was not 100% clear that you could simultaneously do this. so great news!

tks mt
poeCapture.JPG
auto works great as expected too, 1st device is a MT hap ac lite // 2nd device is a poe AF ap from another mfg:

poe3Capture.JPG
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:beep :beep :beep

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