Ubiquiti EdgeRouter X - Power Over Ethernet (POE)

I tested the POE feature of the router this week. I will cover what I did, and the results.

I had a Polycom VOIP phone that was POE-enabled, and I did not have the power supply for it; hence the use case, and excitement about leveraging this feature when I started using this router.

By default, this router uses eth0 as the Management port (192.168.1.0/24), and eth1 as the WAN / Internet port.

This assumes that only a single ISP is being used with the router which is a good assumption considering this is a small consumer appliance and not an Enterprise router.  The router actually supports dual ISPs (link aggregation), which is certainly an Enterprise feature, but to employ this feature you need to change the ports such that you are using eth0 (leftmost port) and eth4 (rightmost port).

The POE feature on this router is POE Passthrough, which means that you need to insert a POE-enabled device into the "input port" - which happens to be eth0 (leftmost port), and POE output will be supplied on the passthrough port eth4.

1. First, I checked the line to make sure it had POE, by connecting it to the phone directly. Voila', it powered up. So, knowing POE was indeed enabled on the input CAT-5 from the patch panel, I set about trying it on the router.
2. Next, I had to reconfigure the router so that eth0 was the WAN port. This meant removing (or moving) the Management port. Since a Management port is handy to have, I made eth1 the Management Port - essentially switching eth0 and eth1. I will skip the details on how to do this, but basically you can do this through the menu system of the device by going to Dashboard, Services and Firewall.
3. I then connected the POE VOIP phone to eth4 - directly. A common mistake is to use a switch, but if the switch is not a POE switch, this won't work (you can also burn up the switch this way). I made sure that eth4 was on the Switch! For some reason, only eth2 and eth3 were on the switch (boxes ticked). I ticked the eth4 box.
4. On the eth4 POE Output interface is where you enable POE. I was surprised you could not enable it on eth0 input link. I enabled this. Keep in mind the router is STILL PLUGGED IN! 

The POE VOIP phone did not power up.  One theory is that the router could not power up the phone on its own, based on just the voltage from the input CAT-5 (keep in mind it also needs to power the router itself). We then powered up the router with the adaptor, thinking this might supply more juice (voltage) to power up the phone. Nope.

I did not have more time to debug this. I disabled POE on eth4, and used a POE Adaptor, which works just fine. Maybe I can attempt this later, but at first test, POE did work. For me. For my phone. This is the first time I have actually used POE.