We occasionally get asked what the deal is with the Power over Ethernet (PoE) on the PC Engines "ALIX" series of single board computers.

It's not the same as the PoE that most IP Phones, IP Cameras and network switches use. To save money on components so you can buy them at such good prices PC Engines decided to use "passive" PoE technology, which is basically sending DC power down the unused pairs of the network cable. The voltage can be anything in the range that the ALIX boards accept (7-20V) which is again different to the 48V that 802.3af PoE uses.

There's a couple of useful products to power the ALIX boards with; firstly the standard PC Engines injector which lets you just use the same jack that you would normally plug directly into the board, but remotely. Then there's the Freetronics 4-Channel PoE Injector, this is much the same thing, but will let you power 4 devices.

If you've already got a PoE Switch powering other things on your network then you can use this neat product from LevelOne; the "POS-1002" PoE splitter. This neat little box converts the 48V from your PoE switch to various selectable voltages and even comes with a selection of output jack sizes which will let you power all sorts of devices, including the ALIX boards.

Hopefully this gives some insight into powering the PC Engines ALIX boards with Power over Ethernet (PoE). To finish off, since we're talking about powering the ALIX boards, here's a neat article with a DIY UPS for the ALIX boards as a bonus.