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cenizass
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HELP: POE OUTPUT

Thu Dec 17, 2020 2:51 am

Hey guys, how are you?

I am writing to answer a question, I have a rb4011 and a unifi AP uap-hd-ac

I would like to know if my mikrotik feeds the AP perfectly by passive poe. The consumption of the AP is 17w
But I don't quite understand the differences between active poe and passive poe.

Cheers
Fernando.
 
mkx
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Re: HELP: POE OUTPUT

Thu Dec 17, 2020 11:09 am

There is standard for PoE: IEEE 802.3af and relatives. However, quite a few vendors came up with their own PoE implementations. In Mikrotik world, "passive PoE" refers to MT's own proprietary implementation, which incidentally is compatible with Ubiquiti's. So in theory RB4011 can power UBNT AP. However, one has to always check power budgets. You're writing that AP consumes up to 17W. RB4011 has PoE out current limit at 600mA when supply voltage is less than 30V and 450mA when supply voltage is above 30V. With originally supplied power adapter (24V) this means around 14.4W output power which is less than AP can require.

In short: it might work, but if you notice any instability in AP's performance it might be due to insufficient power output of RB4011.
BR,
Metod
 
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xvo
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Re: HELP: POE OUTPUT

Thu Dec 17, 2020 11:46 am

UAP-AC-HD needs more than 44V according to datasheet, so 48V power supply is needed anyway.
And no passive poe support is mentioned at all.
So no guarantee it will work from 4011 at all.
Better wait for someone who actually tried it to confirm.
 
mkx
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Re: HELP: POE OUTPUT

Fri Dec 18, 2020 12:40 am

@xvo is right, this particular AP needs 802.3at compatible power source which RB4011 doesn't support. It might work but that's unlikely. Unless somebody with first-hand experience chimes in you'll have to either try yourself or assume it doesn't work.
BR,
Metod

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