[NoCatNet] Power over Ethernet problems

[Gordon Stewart]

This is an FYI to the group on problems I've had with POE.  

POE is Power Over Ethernet which uses a Linksys WAPPOE device using two of
the spare wires in the cat 5 cable to carry power to the device at the other
end - a WET11 in my case.  At the supply end the injector puts 48 VDC on the
unused pair and the splitter at the other end knocks it down to the required
5 VDC which powers the WET11.
 
My setup consists of a WRT54G > POE injector > 50' Cat 5 cable > POE
Splitter > WET11 > antenna.  

I've recently been having frequent interruptions in service where I have not
been able to ping the WET11.  I can cycle the power, fiddle with the cables
and eventually it comes back on line.

The cat5 cable is commercial 50' cable with RJ45s on each end.  I noticed
recently that the RJ45 at the injector end where it plugs into the POE is
blackened as if it has been overheating. There are carbon deposits on the
connectors and it is easy to see how the connection may be impaired.  The
splitter end looks good with no damage.  

During a service interruption this morning I dragged a power cord onto the
roof and installed a 5 volt supply to bypass the POE equipment completely.
The system came on line immediately.  I have now installed permanent 110VAC
power to the WET11 at the antenna.

It is possible that I had a bad connection bewteen the RJ45 and the injector
and this cooked the RJ45.  Perhaps the RJ45 was not designed to carry even
the low power required to drive a remote device.  

Gordon