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Making your own power over Ethernet cable

Making your own power over Ethernet cable

Making your own Power over Ethernet (POE) cable to supply power to your router/access Point/wireless gateway using only your RJ-45 connection.

Keep in mind this works with ANY access point or wireless gateway. Most SOHO wireless routers or access points do not have Power over Ethernet (POE) built into their products. Power over Ethernet allows you to run only a single RJ-45 cable (Ethernet) to your access point, and run the power over the unused pairs of wires within the RJ-45 cable. In Category 5e cables, there are 2 pairs of wires (4 wires total) that are unused and can be used to inject power into your cable. Running power over your Ethernet cable can often save you time and extension cords by trying to run power up to the access point. If you have your AP or gateway in your attic or near your rafters in your roof, getting power up to that location is tough. 

Power over Ethernet is a specification that allows for your router or access point to draw its power internally from the unused pins (4/5 and 7/8) in the cable. Since many routers do not have this, we will “hack” a RJ-45 cable and “inject” our DC power supply into the cable, and on the far end of the RJ-45 cable, we will “extract” the power from the RJ-45 cable before it goes into the AP or gateway. This is not true Power over Ethernet, just a rigged version to help make your life easier!

The first step is to find your power supply for your AP or wireless gateway. Examine the OUTPUT power, most of these are around 9-12v DC. The ORiNOCO BG-2000 that we use for this tutorial is a 9V DC supply. Find out which wire on the power supply is positive and negative. The Agere BG-2000 has Tip positive, and the power supply positive wire has a white stripe in it. (See picture 1 )
Cut your power supply down near the end that plugs into the gateway, leaving about 6 inches. (See picture 1 ) Strip the wiring around each end of the power supply and the cut end. Make sure you keep note of which wire on each end is positive. Put these aside.

Now, take your RJ-45 cable and splice into the cable about 6″ from each end and remove the sheath around a 2-3 inch area on each end. (See screenshot from abive) Our cable is a 25 foot Category 5e by Belkin. Pins 1/2 and 3/6 are the ones we DO NOT WANT TO CUT. Identify the wires 4/5 and 7/8. In our cable, 4/5 is the blue and blue/white wire, and the 7/8 is the brown and brown/white wire. (For help see this site) Cut these wires on the RJ-45 plug end, leaving wires 1/2 and 3/6 intact. Do this on each end of the RJ-45, being careful not to damage or cut any of the other wires. Strip each of the cut wires about 1″ down. Twist the blue pair of stripped wires together, and do the same with the brown pair. Do this on each side of the cable. (See picture 1)

Now, take your POSITIVE stripped wire of your power supply end, and twist that POSITIVE wire onto the blue pair. Take the NEGATIVE wire from the power supply and twist that with the brown pair. (See photos) Now take the small end of the power supply that you cut (See photo) and find the POSITIVE wire. Twist the wire with the blue pair on the other end of the RJ-45 cable. Take the NEGATIVE wire and twist that with the brown pair. Proceed to the testing phase below, make sure your cable works great and then tape it up with electrical tape, making sure to protect the “hot” wires from the network wires.

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