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PoE on CRS112-8P-4S-IN

Posted: Tue May 11, 2021 5:55 pm
by wilmur
Is there a way to get PoE out to power an Avaya phone? Actually any PoE device. I have been unable to get any PoE device to power up using these switches. I have tried different settings for poe-out but nothing seems to activate the units. Is there anything I can do or just scrap poe?

Re: PoE on CRS112-8P-4S-IN

Posted: Sun May 16, 2021 3:45 am
by LSan83
What's the power requirement of the phone?
You have the corrispondent voltage psu connected to the CRS?
24/28v psu can't supply 48v poe.... You need a 48v power supply for that.

Re: PoE on CRS112-8P-4S-IN

Posted: Mon Jun 14, 2021 8:58 pm
by erkexzcx
There are few things that might confuse you:
  • There are 2 types of PoE - one is passive, and the other is 802.3af/at. Passive PoE is 18-28v and 802.3af/at is 48-57v. Switch will automatically detect if device supports PoE.
  • This switch/router comes with 28v power supply, so out of the box your 802.3af/at connected devices will not be powered on.

https://mikrotik.com/product/crs112_8p_4s_in says:
28 V 3.4 A power supply is already included in the box. There is secondary DC jack on the back of the enclosure that supports 48-57 V power supply (not included, can be purchased separately - product codes 48POW (1.46A 70W) and 48V2A96W (2A 96W)).

And lastly, from my own experience, you don't need 28v power supply at all. Connecting only 48v+ power supply is enough to power up passive PoE and 802.3af/at devices. :)


TL;DR buy one of the mentioned power supplies and you will be good.