Objective: Wire up a Power Over Ethernet (POE) cable AND make it provide power INTERNALLY (i.e. no external power connector going into the router. I have limited space in my outdoor AP enclosure, so can't use the power connector).
Tools: Scissors to cut and strip wires (or wire strippers). Soldering gun, solder, flux. Electrical tape or heat shrink tubing. Phillips #1 screwdriver.
Skillz required: Basic soldering skills. Ability to cut the jacket off the middle of a network cable with scissors without damaging any of the wires inside.
NOTE: If you want POE and DON'T want to open your router, then scroll down to the cable making instructions!
1. Rip apart the WRT54GL (just grab the blue part and pull it off the black part, pull hard. There are tons of instructions on here for how to disassemble it.)
3. Next we are going to solder some wires from the unused POE pins on the WAN port directly to the power plug tabs.
I am going to be using the Intel, Symbol, and Orinoco Standard, NOT the Cisco standard for wiring! Do NOT use a bigger gauge wire then 18ga (i.e use 18 or 20).
Pin 4 & 5 - DC Positive (Blue and Striped Blue)
Pin 7 & 8 - DC Negative (Brown and Striped Brown)
Make sure when soldering the wires that it touches BOTH the pins (i.e. 4 AND 5, 7 AND 8 ). Do NOT just solder to one of the pins (I know, it's easier, BUT DON'T DO IT! You'll find out why down below!)
Also make sure to not accidentally solder more pins then you should. It's tricky to not solder pins 2 and 3 by mistake, so be careful.
4. The other ends of the wires we'll solder to the tabs on the power connector. Negative wire goes to the tab on the far right, and positive wire goes to the bottom tab. Just do it like the picture.
*OPTIONAL* 5. Now time to test the POE setup to make sure your solders are good, no polarity reversed, etc. If you take a network cable and cut one end off. Strip the striped blue and blue wires, twist them together (these are positive), strip the brown and striped brown and twist them together (these are negative). You can temporarily test it by pushing the stripped blue wires into the inside of the stock power adapter connector, and then wrap the brown wires around the outside. Plug in the other end of the network cable to the WAN port, and she should light up!
6. Carefully cut the jacket off of the network cable you want to power. You are going to be doing this at the end that you will PROVIDE POWER TO, i.e. the power adapter end. Leave about 12" of network cable, and strip the jacket off of about 2 inches of it. BE CAREFUL to NOT damage any of the wires inside.
After the jacket is removed, cut the brown and striped brown wires right at the edge of the remaining jacket, close to the "short" end of network cable. Do the same with the blue pair. Strip the ends of the pairs and twist the browns together, then twist the blues together.
Now take your linksys power adapter, and cut the power cord about 1ft from the end that goes into the router (NOTE: Leave 1ft!). The striped black wire is the POSITIVE wire, the black wire is NEGATIVE. Twist and/or solder the striped black wire to the blue pair, and do the same for the black wire to the brown pair.
1. What if I don't want to void my router warranty but still want POE?
No problem. Just follow the instructions to make the cable, and do the EXACT same thing again on the other end, but instead of the power adapter, use that 1ft of power adapter cable you have left over (with the stock linksys power connector on the end). Wire it in same as the instructions and MAKE SURE you get the polarity right! (striped black to blue pair, black to brown pair).
2. Whops, I was lazy or messed it up and only wired the power wires to pin 4 and 8 on the bottom of the router!
No big deal. The only problem is that you'll get WAY more voltage drop on long cable runs. Go to this website and calculate your voltage drop. The WRT54GL works great as low as 5.5volts or so. That's over the max CAT5 spec of 326ft even with a single wire (as long as you don't have any fans in your router, etc.). Actual voltage with a single pair at 326ft would be 8.7v, plenty to run it.
Note: Change pairs to "1" if you only connected your wires to one pin each. Set input voltage to 12v, input current to .42 (AND NO, IT'S NOT 1 AMP like your power adapter says!), etc.
3. What kind of interferance will the power going through the ethernet cable cause?
Absolutely NONE! Period. If you're trying to run 110AC and put the actual linksys power adapter in your AP enclosure, then there might be interference, but 12v DC definatly doesn't cause any.
4. Instead of cutting the wires in the network cable, I just shaved them and soldered to them. Can I now use POE to power all 48 devices plugged into my switch?
Ummmm. No. Pins 4,5, 7 and 8 are usually never connected in the switch, modem, etc. The reason that I had you CUT the wires, so is power doesn't feed back into your switch, cable modem, etc. etc. Now, it wouldn't cause any damage, but the stupid 48 port switch that we have at my work has pins 4, 5, 7, and 8 ALL SHORTED TOGETHER! Something to reduce emi noise or something!? So, I had to make sure power didn't go back that direction otherwise it'd short out the power adapter.
5. What do I do with the left over 1ft peice of power adapter cable (with the linksys power connector on the end)?
Keep it for a rainy day. If your router dies and you replace it, you might want to use this cable to connect the power to it, rather then voiding your warranty and opening up the new router.
Feel free to ask any questions or ask for more pics if needed!?
-Jamie M.
Last edited by toysareforboys on Mon Dec 06, 2010 19:10; edited 9 times in total
Joined: 09 Aug 2007 Posts: 36 Location: Toronto, Ontario, Canada
Posted: Fri Aug 10, 2007 1:36 Post subject:
hehe. Thanks.
I've been using DD-WRT forever, such a great product! I've never donated or purchased the "premium" version or done anything else to support them, so I figured I better damn post some useful info on here .
It really makes for a nice clean setup. The other two techs at work did a double take when they seen it lit up with no power cable, they thought it was battery powered .
Joined: 21 Apr 2007 Posts: 86 Location: Buenos Aires
Posted: Fri Aug 10, 2007 2:40 Post subject:
Nice post toysareforboys!
I did this, and I would like to recommend some minor modifications.
Cut the RED cable (Between the RJ45 and the + connector, and add a 1N4007 Diode with the positive pointing towards the connector)(in series I mean) this will help in case that you accidentally reverse the polarity, the router won't receive any power, so there is no risk (also no need to remember which polarity was it, just try since the diode would prevent to kill the router in the case of reversed polarity )
Another one would be to add a polyswitch MF-R110 or MF-R090 or similar (1.1 A and 0.9A) in the other end of the POE, (in series with the positive of the power supply, as if it where a fuse)
This is, in case of some kind of short, won't blow the power supply, the polyswitch will open the circuit (as a fuse would) and as soon as the short goes out will connect again
No need for a diode. 54g already has a built-in protection for reverse polarity. Actually, every modern electric device has that function built in nowadays.
I should add one thing. The ampherage of the supplied power from Linksys is 2.4A not .24A. 12v x .24A = 2.88W 54g consumes less than 6W but not at 2.88W. Since wrt54g consumes less than 2.4A, there are almost no chance of burning the cat5 cable. But, it'd better get a regulated power supply that delivers less than 1.4A for a safety measure.
Joined: 09 Aug 2007 Posts: 36 Location: Toronto, Ontario, Canada
Posted: Fri Aug 10, 2007 4:11 Post subject:
nskim wrote:
The ampherage of the supplied power from Linksys is 2.4A not .24A.
Hmmm. My linksys power adapter says right on it: output 12v, 1amp. I used a meter at work and under load (wireless at 84mw, four pc's wired in), current draw was only 420ma (.42amps)!
*edit, my bad. Was 420ma, not 240ma . I corrected the article.*
Joined: 21 Apr 2007 Posts: 86 Location: Buenos Aires
Posted: Fri Aug 10, 2007 12:51 Post subject:
nskim wrote:
No need for a diode. 54g already has a built-in protection for reverse polarity. Actually, every modern electric device has that function built in nowadays.
You are right!!, I poped out the case of the WRT54GL and there it was, A series capacitor, also there is Polyswitch like the one I talked about, (the flat yellow thing between the two imput filters near the power connector). :)
Joined: 09 Aug 2007 Posts: 36 Location: Toronto, Ontario, Canada
Posted: Fri Aug 10, 2007 16:06 Post subject:
redhawk0 wrote:
Great stuff...but I keep LICKing my screen for the High Res pics.
So...how long an Ethernet line before the line drop is too great to run the device
hehe. Whops, CLICK, damn copy and paste .
Well, assuming you wired and soldered BOTH pairs properly, and are using standard 24ga CAT5 cable, don't have any fans in your router, etc., here are the specs:
100ft actual router voltage = 11.5v
150ft actual router voltage = 11.3v
200ft actual router voltage = 11.0v
250ft actual router voltage = 10.8v
300ft actual router voltage = 10.5v
326ft actual router voltage (maximum CAT5 length spec) = 10.4v
If you only wired a single pair:
100ft actual router voltage = 11.0v
150ft actual router voltage = 10.5v
200ft actual router voltage = 10.0v
250ft actual router voltage = 9.5v
300ft actual router voltage = 9.0v
326ft actual router voltage (maximum CAT5 length spec) = 8.7v
Now, stick a fan on there, and it's only 3.7v at 326ft (single wire), or a respectable 7.9v with both pairs!!
Like I said, I ran the WRT54GL down to about 5.5v (9v power adapter and 275ft of dual pair CAT5 just to test) and it had no problems.
So, to finally answer your question, the maximum cable length you could run and sucessfully power your WRT54GL would be 1400ft (5v)! At 1000ft, the voltage would be 7v at the router (with both pairs wired).
-Jamie M.
Last edited by toysareforboys on Sat Aug 11, 2007 1:00; edited 7 times in total
Joined: 01 Sep 2006 Posts: 92 Location: Netherlands, The Hague
Posted: Sat Aug 11, 2007 15:07 Post subject:
Nice tutorial! I did that to my WRT54GL last month too... Wanted to get rid of the butt ugly wall wart in the livingroom.
Instead of making a dedicated POE CAT5 cable why not make your own POE injector and splitter? That way you can use any CAT5 cable (no crosscable!) you may have lying around. I first made both an injector and a splitter. Soon after that I voided my GL's warranty by opening it up and do the power/data splitting inside of the unit.
Here's the image of my splitter doing its work at the GL side. At the moment it gets its power throught the CAT5 cable in the WAN port. The injector I made is similar in appearance.
Joined: 09 Aug 2007 Posts: 36 Location: Toronto, Ontario, Canada
Posted: Sat Aug 11, 2007 18:59 Post subject:
Yep, I coulda made injectors and splitters, but It wasn't required for my outdoor AP at the moment, and I tried to make the tutorial only requiring a soldering gun, absolutely no extra parts, and not even needing a soldering gun if you don't do the "internal" POE part of the mod .
I always like mods where I can hack into it and do it right now, no need to run to future shop, best buy, radio shack, etc.