Linksys Wrt54g Router Mod - Run Without Power Supply

[dserban 0]

This is a set of apparently well illustrated modification instructions to allow you to run your WRT54G router without external power supply.

http://www.linksysinfo.org/index.php

The site is very, very popular at the moment, so you may have to bookmark the page to check it later. Although this is a website dedicated to routers and networking products, I was barely able to pull the bare bones page down using wget. They may think of putting a leaner version of the page at some point.

Anyway, the trick does not consist in somehow squeezing a battery pack inside, but instead there is a simple modification inside the router that implements Power Over Ethernet (POE). You can power the router through the CAT5 cable.
So instead of having a power supply plugged into your router, you have a power supply plugged into the other end of a CAT5 cable. Still a power supply.
By reading around some more, some people suggest that this isn't even a mod. Their WRT54G routers have never had the power supply plugged in, they have just always been powered over the Ethernet.

Below the text I was able to pull down with wget:

HOWTO: WRT54GL DIY Internal POE! *pics* ------------------------------------
Ok, on the operating table today, fresh outa the box {WRT54GL} v1.1

{[Click here to see the larger version]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.)

{[Click here to see the larger version]

If you are having trouble getting it apart make sure you have destroyed the "Do not tamper with brains inside" sticker on the bottom.

{[Click here to see the larger version]

{[Click here to see the larger version]

2. Remove the two #1 phillips screws in the middle of the motherboard and slide the board forward and pop it off the black base plate.

{[Click here to see the larger version]

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)

{[Click here to see the larger version]

{[Click here to see the larger version]

{[Click here to see the larger version]

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.

{[Click here to see the larger version]

{[Click here to see the larger version]

*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!

{[Click here to see the larger version]

{[Click here to see the larger version]

Instructions for making the POE cable!

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.

{[Click here to see the larger version]

7. Electrical tape all the connections, and do a nice tight wrap job and make it look all pretty. Plug her all in and give her a test!!

{[Click here to see the larger version]

{[Click here to see the larger version]

Look maaa! No power cable! .

FAQ's:

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 lower, so that'd be over 500ft of cable if you wired both pairs, or only 250ft if you only connected 1 pair!!

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 it says on your power adapter!), etc.

{http://blog.fosketts.net/toolbox/power-ethernet-calculator/}

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.