LaFonera Hardware Power-over-Ethernet
From DD-WRT Wiki
Someone should find some information or write a little tutorial.
One solution might be to use DC/DC-converter inside LaFonera. For example RP10-4805SE from Recom. These units are quite expensive, several 10´s of euros each, but might be ideal in this case.
 Just some preliminary notes
LaFonera is, I think, identical to an SMC unit we use (looks identical when opened up, same circuit and component placement). This information is based on our experience with the SMC unit.
Problem #1: Unit runs on 5V 1A PSU. Behaves erratically at <4.5V (Does not even boot up) - and the on-board components are rated 7.5V; Standard PoE is 48V. 12V usually works too. We are pretty sure you'll fry your LaFonera with 12V, let alone 48V.
Problem #2: 5V does not travel for more than 5m through CAT5. 12V 1A should be sufficient to run the unit at up to 160m of CAT5.
Our Solution: We have installed a 5V power regulator (7805, wide input range from 6,5 to 35V) attached to a pentium heatsink, to run our units. The heatsink heats up quite fast (~80 degrees Celsius). Has run stable for 6 months over 30m of CAT5. (It does run very hot and I'm surprised the box hasn't melted in our summer heat which easily reaches 40 degrees Celsius) Alternatively you should build a switching-mode step-down DC converter, Schematic. Realisation It emits MUCH less heat.
Standard ethernet wiring: White-Orange, Orange, White-Green, Blue, White-Blue, Green, White-Brown, Brown. Both blue pairs are connected to and both brown pairs to -. Its not worth the hassle soldering a connection to the ethernet connector and we simply attached these pairs to the standard 5V power in plug, in the box where the unit is to be mounted.
We have tried running two units in series, off 12V, with no PT's, but the power drain cycles when under load and idle cause the voltage to jump too much and inevitably either unit ends up crashing/rebooting - if they manage to start up.
Ideal solution would be to have 2 LaFoneras in series, each with it's own power regulator to step down and stabilise the voltage. Having two units would keep the heat on the PT's heatsink down quite a bit. One unit can function as an AP and the other as a bridge. Or both can run as bridges. Ideal low-cost repeater solution.
 Build an POE adapter
DIY Power over Ethernet + F*nera modding http://www.hobbielektronika.hu/kapcsolasok/power_over_ethernet_hazilag.html
 Buy one
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