Power Over Ethernet Router Conversion




The idea driving this project is to turn any standard, off-the-shelf router into a Power Over Ethernet (PoE)-capable (Wikipedia Description)[] unit without buying any adapters or additional hardware.

PoE is somthing fairly common in many business/office spaces. For example, many wireless access points in office buildings and universities use the technology so they don't have to run a power receptacle to wireless access points. For this instructable though, we're going to use PoE in a residential setting. Even the big router companies are starting to sell these adaptors to consumers like this Linksys WAPPOE12. But I think it costs way too much and is kinda bulky. If you're into the DIY bulky thing though/have a need for an external PoE injector, you could try this option.

Applications for this instructable are up to your imagination. You might be relocating your wireless router to the centre of a house for better reception even though the cable modem installer might have put the cable modem say in the basement/some other inconvenient spot. Another useful application might just be to make an all weather-sealed outdoor access point with the famous WRT54G router inside it.

In my case, I will be using a 5 year-old WIRED router that I had lying around. Have no fear though, the points where we will be soldering are identical on every router/switch that you can get today. I should note that we're using cat5 here. If all you have is cat6, you can still go ahead and use that. But I should note, if you're connecting to a gigabit ethernet device, this instructable won't work. Luckilly, cable modems don't work at GigE speeds and I doubt the WAN port on your router supports GigE.

To begin we'll need some basic things:
1. A router
2. A length of cat5 cable (length depending on your location...mine was 10 ft.)
3. RJ-45 connector ends (...ok 8P8C for you technical people)
4. RJ-45 cable booties
5. A wall wart (power supply brick)
6. Some heat shrink tubing (I just used some random scraps I had lying around)
7. Your trusty soldering iron and some solder

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Step 1: Open It Up!

First off let's unplug everything from the router. Not just power but the ethernet cables too that will otherwise get in the way of things.

Next, we'll open up the router. Be careful though before you, start prying off the plastic casing and it snaps. There's usually a screw hidden under the label with the serial number, etc... on the bottom of the unit. It's the indicator for the manufacturer to see if you've voided your warranty. Oh, and by the way, this instructable\ will definitely void your warranty. Something I take no responsability for.

Step 2: Bypass the DC Power Input

Now that the case is open we can pop the board out and start soldering. Actually, the soldering here is pretty simple -- and this is coming from someone who rarely solders. All we're doing is bypassing the DC power input, the barrel connector that would attach the wall wart to the router.

In my case, I wasn't sure if I'd want to use my router as an actual router or simply as a switch. With that in mind, I decided to make the first port on the router's built-in switch the "injector port." If you were connecting your wireless router to a cable modem you'd just connect it to the port labeled WAN/Internet instead. The process is the exact same as the one I'm following though, just the port is in a different spot. Cycle through the pictures and you'll see the modified instructions for using the WAN port instead of the first port on the switch.

Regardless of what port you chose to use, you must solder pins 4 and 5 to the red (or POSITIVE) lead. Then you solder pins 7 and 8 to the black (or NEGATIVE) lead. Be careful though, ensuring that you don't get sloppy with your soldering and say, link pins 6, 7, 8 together. It can be a little difficult soldering areas that are so close and so small.

The next part is a little hard to explain just in words so definitely check out the pictures. In the bottom of the first picture, you'll see the DC power input area. Normally, the barrel connector from your power brick would connect here to the router. We're going to eliminate the need for that barrel connector port here though. In this particular example, the barrel connector port is facing DOWN. This matters quite a bit. Many of you might be soldering with it point up. Don't want to mix the polarities up at all.

Mouse-over the pics to see what pins need to be soldered where and definitely zoom in.

In my case,

Step 3: Make the Power Adapter End

To finish off the project, we have to make a cable that will connect our computer to the router for LAN access as well as connect our router to it's newly defined power input. The process is fairly simple:

1. Measure out about 15 feet of cat5 cable. I say 15 feet as a guideline...some believe anything over 15 with this technique is dangerous. However it's debatable. The above linked wikipedia article makes references to this, but before you solder (anything) measure the resistance of your length of cable in step 3 of this list.

2. Use a cat5 cable stripper (come free with many jacks) or an Xacto knife to gently score the sheathing of the cat5 cable 3-4 feet before the cable ends. This is the end that will connect your DC power supply to the computer's power bar and the ethernet port on the computers network interface card/motherboard. Be careful when stripping though, you don't want to nick any of the twisted pairs inside the cable sheathing.

3. Pull the last 3-4 feet up to give you 3 inches of cable exposed. Now we can see the twisted pairs. Cut the blue and brown pairs out as illustrated. Strip the 4 pairs of their sheathing and then twist brown and brown-white together and push off to the side. Then twist the blue and blue-white pairs together. If you want to see the resitance of your cable, connector your multimeter's teast leads to one of the twisted pairs and check on the short end of the cable.

4. Before you break out the soldering iron, prepare the DC injector end by cutting the cable in half (or any other length you prefer...longer might be better if the power bar is say, on your desk). Then strip off the plastic about half an inch or so on both ends. Pull the two wires apart for about a 3 inches and then slip about 1.5 inches of shrink tubing down both ends.

4. However, before we solder anything make sure you have the right polarities figured out. The twisted together blue/blue-white wires get soldered to the positive wire. In our case, this is marked with some writing on it by the manufacturer. Simply twist the two together and solder. Then repeat the process, twisting together the brown/brown-white wires with the negative wire on the connector.

5. We're almost done here. Now, just slip the shrink wrap over the wires you just soldered and use a heat gun or torch to shrink. TIP: I couldn't find my heat gun...so I just moved the soldering iron down the tubing leaving half an inch or so of space between the tubing and iron. Next, slide up the wider piece of shrink tubing (in my case it's white) up to cover those shrunk connections. I'm usually quite thorough with this step of the process -- you don't want anything making contact and shorting out.

6. Last, we'll slip on some cable booties and terminate the ends on this injector cable.

Step 4: Conclusion

Plug the thing in, wall-mount/enclose outside if necessary and surft the internet with less wire mess in your life. One idea that I may try in the future is to get rid of the wal wart altogether and connect the PoE injector end into the tower's PSU. The floppy connector spits out 12 volts of power, meaning the wall wart wouldn't even have to be hidden inside a tower!

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    29 Discussions


    8 years ago on Step 4

    If you do like you said and use your computer's PSU to power your router, be sure to tap a 5 volt source instead of a 12 volt source, routers don't work very well after you've let the magic smoke out!

    2 replies

    Reply 8 years ago on Step 4

    Good advice!

    I'd approach it from more of a "know the max voltage of the router" point-of-view though. Taking the red (+) and black (gnd) wires will give one 5 volts of power and a ground. Yellow (+) and black (gnd) wires will give you 12 volts.

    It really depends on the minimum voltage the router requires to operate. For my Linksys WRT54G and WRT300N, both can run on either the 5 volt or 12 volt connections (they each have a LM7805 IC inside to regulate the voltage). On the other hand, my Belkin F7D3302 will not run on anything but the 12 volt.


    Reply 4 years ago on Introduction

    I fully support your "know the max voltage of the router" approach. I would like to add a remark though:

    In general, an LM7805 integrated circuit (IC) will need at least 7 or 8 volts to create a steady 5V supply. So if you feed it just 5V I would be surprised if it works properly.


    11 years ago on Introduction

    So this lets you power your router using your Ethernet cable AND it lets you surf the web. I'm sorry I couldn't understand quite well.

    2 replies

    Reply 11 years ago on Introduction

    LOL. I just read the Wikipedia description and I guess it does what I thought it does. I guess I should read before I write. LOL.


    10 years ago on Introduction

    Could you have 2 devices that need power like a hub and a switch and run them off the same wall adapter? The voltages will be the same.


    10 years ago on Introduction

    actually I have antenna internet through Internet America and the power is provided to the equiptment through this method, there is adapter that uses the other 4 unused wires to transmit 12volts to the equiptment on the roof thus getting rid of the need for 2 wires.


    11 years ago on Introduction

    I'm really green when it comes to being technically literate and this is the first site I have discovered like this. I love the concept so please excuse me if I don't communicate what I need to know correctly. But, I wonder if you would be kind enough to tell me did I need a wireless router in the following situation: I'm setting up my 1st ever home network because I have a desktop which only has USB ports (older that has no ethernet port) and a newer computer that has wireless. Purchased a wireless router so that both computers would have an IP connection through my cable modem which has both an ethernet and USB port. Talked to tech support of the manufacturer of the wireless router and was told that I also need to get a ethernet adapter. Not that I'm cheap or completely ignorant (computer challenged wise) but is there an alternative or are they just trying to sell yet another product they manufacture? I really think if this site is what it appears to be to me, that you all sharing the knowledge you have or have gained by communicating your insites to better one's understanding of a topic, by doing so your sharing a valuable asset which is knowledge! Let me know what you think. Thanks.

    1 reply

    11 years ago on Introduction

    Um. Real "Power over Ethernet" is a lot more complicated than this: 1) It doesn't provide power unless the "powered device" asks for it, to avoid zapping devices that only expect data on those pins. 2) It allows power and data to share the same wires/pins. 3) voltage is typically 48V (a standard telco voltage.) So this instructable tells you how to wire up a router to provide SOME power on the unused wires of ethernet cables, which may have some valid uses, but it's NOT really "PoE", and it won't be compatible with commercial products that expect to get their power over PoE. (grr. It's a real shame that real PoE is some complex and expensive (and not very energy efficient, either, since your central switches suddenly have to have supplies sufficient provide power for ALL possible ports whether or not anything is even plugged in.) A while ago I was looking for a low-cost PoE solution for smaller projects (say, a 3 watts module), and I couldn't find ANYTHING. (there's a fair amount near the top of PoE at 12+W.))

    8 replies

    Reply 11 years ago on Introduction

    oh,I am caught off guard NO 10/100 ETHERNET!! JUST GIGABIT! now im all screwed up(jk)


    Reply 11 years ago on Introduction

    A good point indeed if your daisy-chaining or connecting to a GigE source. I guess I should just clarify that this mod would be best suited for powering wireless/wired routers/access points at 10/100 Mbps -- devices that would need to be in an odd place. In that situation you'd run some cat5 from your modem end (have the wal wart on that end) and then connect the modem signal/power cat5 cable to the uplink/internet port on the router. You don't need GigE to connect a high-speed modem, especially when you consider that the highest speed FiOS connection will "only" give you 50 Mbit/s Downstream / 20 Mbit/s Upstream. You don't have to worry about causing interference as we're pushing 12 volt direct current power of the two pairs which isn't like that nasty AC stuff in your walls.


    Reply 11 years ago on Introduction

    <a rel="nofollow" href="http://www.l-com.com/item.aspx?id=9503&cmp=ALSOS">http://www.l-com.com/item.aspx?id=9503&cmp=ALSOS</a><br/>I dont know what you are looking for but I may have some other links. <br/>Hyperlink tech is one other place. I have possiblyone more place to send you if you need it. <br/>They used to have a bunch of poe stuff at great prices. <br/>sunset1<br/>


    Reply 11 years ago on Introduction

    That's effectively what I tried to avoid buying. But handy if you have something that requires the 802.3af specification to function. Essential this instructable is to teach you 1) how to make your router "PoE"-compatible (in a home brew sense) and then create the injector. I'd just like to stress that you couldn't buy one of these and make any device PoE compatible without internally modding the pcb inside the ethernet device.


    Reply 11 years ago on Introduction

    Correction: you could use this device to power a router. But my concern with it is it doesn't make the router "PoE compatible" internally. You have to use an 8p8c adapter that breaks out to a barrel-type connector at the other end. I know I sound picky...but I'm a minimalist when mounting equipment beyond the desk.