Can I power an ePMP with 24V POE, like Mikrotik RB750UP

Currently I am using an RB750UP to power my Rocket M5 ubiquiti radios. I am switching over to cambium from Uniquity and am running a solar array that is connected to two 12V batteries to give us 24V. From what I can see the 750UP will power a device equal to the power input, so 24V in will power a 24V device through POE. So, can the ePMP GPS connectorized radio work with 24V input from this POE? Thank you 

you'll need to re-crimp your cables to do that.  

the 2.4 ghz CPEs will take ether power.

i don't belive the APs will.  if not, re-punch your ethernet cables swapping the brown and blue pairs on one end of the cable and the APs will get the power how they need.  

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You can use 24V POE, like Mikrotik RB750UP to power-up any non-GPS unit, but you have to twist pairs as it was suggested. Please find attached the illustration how you have to twist pairs to power up non-GPS ePMP unit. 

Please remember that non-GPS units accepts 12-30V DC, and GPS power supply should be 30-55V DC(802.3af compatible).


Also, there are ready made POE Crossover Cables, like these.  They cross +/- from 4/5 and 7/8.


I guess this brings up another question, We have been using the "B" wiring schematic starting with with orange, does the same principal apply? we would swap out 4,5 - 7,8?  Since we are running a solar array that ties two 12V batteries inline to create a 24V power system ( and we are using a 24V solar panel) is there a router similar to the RB750UP that can accept a 24V input, but is able to put out 30V to run the ePMP 1000 with GPS?  Thank you.

"B" and "A" are for straight through and cross over.  This involves pins 1/2/3/6

Passive power involves  4/5 and 7/8.  "Normal" is positive on 4/5.  ePMP, pmp100 and pmp450 are the opposite of this.


But as far as we all know, there is not a router that can be powered by 24V and POE out to 30V?

There are number of switches in the market with 24V DC input and 802.3af(48V DC) output: cisco, mikrotik, tycoon power and etc. You can use any of them to power up cluster of GPS APs.

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@Dmitry Moiseev wrote:

...Please remember that non-GPS units accepts 12-30V DC, and GPS power supply should be 30-55V DC(802.3af compatible).

It was my understanding that ePMP 1000 GPS radios would accept 802.3af, typical Canopy reverse polarity PoE, and standard polarity PoE. The spec sheet states an input voltage of "23 to 56 V" for the unit. Has this range changed?

Hi Uberdome,

Thanks for your comment! No, it doesn't change. I usually recommend narrower range(30-55V) to be on a safe side and avoid issues with voltage drop on long cable. If you know what you are doing, then you can follow the spec  "23 to 56 V".

Also , you only have to twist the pairs on the 5Ghz non-gps radios. All of the 2.4Ghz ePMp, both sync and non-sync, will work with reverse or normal polarity unless they have changed the 2.4Ghz non-sync radios recently.

I am new to Cambium radios - just about to deploy my first as a test.  Before I destroy a radio, I want to make sure my brain is clear on this...  I have an ePMP 1000 that I was going to simply connect to my Netonix 48v POE switch using a standard Ethernet cable (using the 568-B wiring standard).

Will this work or do I need to build a special cable or do I have to use the Cambium power supply?  I'd prefer to have them going into my switch for power.

Sorry if this is a silly question.  Coming from years of Ubiquiti use so this is my first use of Cambium - but I am excited!


You can power up GPS sync unit from your 48V switch using your usual cable.

You will burn any non-GPS unit with 48V switch, so we recommend use 24V switch or Cambium power supply.



So Netonix 48V (0.75A) should work on GPS APs?

Turns out, that ePMP can be powered by the RB750UP with no problem. No crossing of cables or anything. Not sure about other Cambium products but GPS sysc AP works fine, at 24V. 

I don't think so. 48V is too much power for ePMP. I think it can take up to 35V or something like that. 

48V is fine for the GPS radios (up to 56v, actually), but for the non-GPS radios (all the SMs) you want to keep it under 30v.

Powering a GPS ePMP radio or Force180 (and I believe Force 200) from an RB750UP will work fine without crossing cables or anything, but that is not true for the connectorized 5ghz SMs (non GPS radios) and the integrated SMs - it will work to power them from an RB750UP, but you would need to swap 4/5 and 7/8 in the cable.

I believe that the GPS Sync radios have heaters in them and you may find when it is cold enough for these heaters to kick on that the radio will not be able to boot on the 24v power supply.  At least that is what we think was causing us problems on AP's with 24v power sources . We think that the cold weather bug would cause the radios to reboot and then when they tried to boot back up with their little heater resistors running the 24v PS couldn't feed them enough power to start back up.  If you are were it gets very cold you probably want to use 30v ePMP power supplies or a 48v power source.


There are two KB articles that will help undertand ePMP power spec under cold temps and using a CMM.