I created this adapter so that I could use a UPS (battery backup) located upstairs, to power a network switch located downstairs. The network switch provides a network/internet connection to my Xbox360, Modded original Xbox, and goes through the basement to a joining house. This solution keeps all of the network equipment powered up, in case I lose power.
This can also be used to power a router, switch, access point or hub that is located in a area that does not have power. For example, you may want to use this method to relocate a WiFi access point to the attic or in a drop ceiling at the office.
The Commercial Linksys POE power injector adapters go for around $40. Power injector adapter
I had the materials on hand which is what prompted me to do this project. You should be able to pick up the materials for under $8...given that you already have a spare Ethernet cable lying around.
2 - RJ45 Ethernet (cat5) wall plate jacks.
1 - RJ45 Ethernet (cat5) patch cable.
Step 1: What Wires Are Actually Used for Data?
A ethernet (cat5) cable has 8 wires. 4 of the wires are used to transmit and recieve data. The other 4 are not used. The "unused" wires will carry the power from the AC adapter.
Step 2: Striping the Ethernet Cable and Sorting the Wires.
Cut the Ethernet (cat5) cable and strip the outer insulation from the cut end, about 1 inch should be enough. You will see 4 groups of wires that are bundled in 2's. Separate the wires. You are only going to use the Green, Green/White and Orange, Orange/White. The other wires can be cut away. Do the same to the other piece of cable.
Step 3: Cutting and Striping the AC Adapter Wires.
Find the middle of the AC adapter cord and cut it. Separate the wires by splitting them apart about 1 inch. Strip the ends of the wires about an 1/8 of an inch. These wires will be pushed onto the RJ45 jack. You will only need to expose a small bit of the wire to make contact on the ethernet jack. Do the same to the other cut piece of the AC adapter.
Step 4: Match the Colors to the Ethernet Jack.
Take the striped end of the ethernet cable and punch each wire into slot 1,2,3 and 6 of the Ethernet jack, using a punch tool or a narrow knife. I would hesitate to go by the colors marked on the ethernet jack. To ensure that the wire colors are correct on both the Ethernet jack and the Ethernet plug. Plug the other end of the Ethernet cable into the jack. This will help you see what color wire goes where on the Ethernet jack. Slots 4,5,7,8 should be empty. Do the same thing to the other ethernet jack and ethernet cable.
Step 5: Powering the Ethernet Jack
Take one of the striped ends of your ac adapter. You will notice that one of the wires will have a white stripe or writing on it. Lets take the marked (striped) wire and push it into slot #8 of the ethernet jack. Take the non-marked wire and push it into slot #4. Take the other striped piece from your ac adapter and do the same to the other ethernet jack.
You should now have 2 parts. One will have the AC adapter power block connected. The other will have the AC power plug connected. ( as pictured). Use electrical tape to secure the AC wire to the ethernet cable. This will help to relieve the strain on the AC wires.
Step 6: The End Results
My router and UPS are located upstairs. I plug the AC adapter into the battery side of the UPS. I then connect the ethernet plug into the router. I then plug in 30ft ethernet cable that runs downstairs to a network switch. The switch uses the other adapter to provide power and network connection.
This solution allows you to use any length of Ethernet (cat5) cable between the devices.
*Note -- This method may not work on Gigabyte devices, since all 8 wires are used. This should only be used on 10/100mbps base network devices.