PoE (Power over Ethernet) How To - NYCwireless: "A number of Access Point manufacturers (Lucent, Symbol)

are now offering Power over Ethernet add-on's for their Access Points.

A PoE module inserts DC voltage into the unused wires in a standard

ethernet cable (pairs 7-8 and 4-5). The idea is to supply the AP's

power and UTP ethernet connectivity requirements via a single ethernet

cable. This works great in areas where you may not have power and/or

ethernet easily accessible, like a roof. This also allows you to more

easily place the AP closer to the antenna, thus reducing signal loss

over antenna cabling. Ethernet signal travels well over CAT 5 cable;

2.4ghz signal doesn't do as well over antenna cabling. Also ethernet

cabling is much cheaper than antenna (LMR-400) cabling. There are

currently two types of PoE adapters: a module jack or hub-like device

for multiple access points. The following hack creates a simple PoE

module pair."