TX1012 24V POE over 20+mtr cable = Ubiquiti radio rebooting


I have multiple cnMatrix TX1012-P-DC Ethernet Switch’s running 4.3-r3.

With 1 x Ubiquiti PBE-2AC-400 connected to port 5, 1 x Ubiquiti R2AC Prism connected to port 6. Passive 24V POE enabled on both.

When I use short patch leads to run this up on the bench, they work fine.

When I deploy to the field (with the R2AC up a 20Mtr tower, Powerbeam only 5mtr up) the R2AC reboots every few minutes, and the TX1012 reporting the link going up and down rapidely.

I have tested this back on the bench with a second TX1012, new R2AC and new 20 mtr ethernet cables.

The TX1012’s is incapable of providing stable 24v passive power to a ubiquiti device over a long cable. I have had to resort to running a seperate POE injector for the R2AC to keep it online.

Please advise any possible remedies to this situation.


Welcome to the Cambium community.

There is a Cambium Field Service Bulletin that addresses this problem

The solution is to use a PoE converter, such as

This converter tells the switch the port needs to be 802.11af, and the output of the converter is passive 24v.

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