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.
The 12 volt Apple Airport and the UGate 3300 use a 2.5mm Inner Diameter and 5.5mm Outer Diameter Coax DC Power Jacks. Other Access Points may use different sizes. (Original Linksys WAP11 [5 Volt, 2 Amp] uses 2.1mm Inner Diameter, New Linksys WAP11 uses a 5.5mm Outer Diameter and 2.5mm Inner Diameter)
By using less expensive Wall Mount Modules (not CAT5 spec), or not using them at all, you can reduce the parts cost of this project.
Step by Step
1. Solder wires to the DC Male Power Plug. Solder one pair (2 wires twisted together) to the inner contact connection. This will be the positive power wires. Solder another pair to the outer-contact connection. Notice that on this DC Male Power Plug there are 3 connectors. One is for the center pin, one is for the outer surface, and one goes to the plug housing. You do not need to solder anything to the plug housing connector. This is what it should look liked when finished.
Soldered DC Male Coax Power Plug
New 2 Port Housing Opened
2. Drill a hole in your two-port mount housing. Mount the Male DC plug in the housing. DC Plug Mounted in 2 Port Housing
3. Connect the wires in your 2 port jack as follows (also refer to Diagram at bottom of page) [Note: this is the Intel, Symbol, Orinoco Standard, not the Cisco standard for wiring.
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