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

**URL:** https://community.cambiumnetworks.com/t/tx1012-24v-poe-over-20-mtr-cable-ubiquiti-radio-rebooting/91505
**Category:** cnMatrix
**Created:** [March 7, 2023, 12:55am UTC](https://community.cambiumnetworks.com/t/tx1012-24v-poe-over-20-mtr-cable-ubiquiti-radio-rebooting/91505 "2023-03-07T00:55:10Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Geoff\_Price](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/g/a88e4f/32.png) [@Geoff\_Price](https://community.cambiumnetworks.com/u/Geoff_Price)
#### Post date: [March 7, 2023, 12:55am UTC](https://community.cambiumnetworks.com/t/tx1012-24v-poe-over-20-mtr-cable-ubiquiti-radio-rebooting/91505/1 "2023-03-07T00:55:10Z")

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Hi,

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.

 ![image](https://d1okf4ta8xniw3.cloudfront.net/original/3X/c/7/c7b4a569bd2e4dc145ceb0a44016cbf10d619fee.png)

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.

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<div class="post-metadata">

### Author: ![DaveClelland](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/d/85f322/32.png) [@DaveClelland](https://community.cambiumnetworks.com/u/DaveClelland)
#### Post date: [March 7, 2023, 2:59pm UTC](https://community.cambiumnetworks.com/t/tx1012-24v-poe-over-20-mtr-cable-ubiquiti-radio-rebooting/91505/2 "2023-03-07T14:59:35Z")

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Geoff,

Welcome to the Cambium community.

There is a Cambium Field Service Bulletin that addresses this problem

> [@Field Service Bulletin - cnMatrix TX switches susceptible to unexpected behavior when devices that require low voltage passive PoE are connected](https://community.cambiumnetworks.com/t/field-service-bulletin-cnmatrix-tx-switches-susceptible-to-unexpected-behavior-when-devices-that-require-low-voltage-passive-poe-are-connected/90874):
>
> cnMatrix TX switches susceptible to unexpected behavior when devices that require low voltage passive PoE are connected. Based on our testing, the current list of affected devices are below. We will continue to update this list if other devices are found to exhibit the same behaviour. Ubiquiti LTU Rocket Ubiquiti AF-5XHD Mimosa C5c Cambium 3000L

The solution is to use a PoE converter, such as  
 ![image](https://d1okf4ta8xniw3.cloudfront.net/original/3X/4/9/49a76cba0e88ba491afc05739abcb61d67b53918.png)

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