I like to play around quite a bit with the fimrware on my WNR3500L router and more than once I have bricked it and had to turn to the directions shown here.
But I have taken it a 
step further and made it so I can plug the special USB cable directly into the router. Now I don't have to have wires hanging out or leave the case open for easy access.
Here is what I did.
I purchased a threaded stereo mount jack, like this one, available at radio shack for $2.50.
Then, instead of buying the special bare wire or SIP cable I bought this cable whcih features a stereo type plug in.
With this, all I had to do was drill a hole in the side of the box and use the nut that comes with the jack and attach it to the router as shown here.
Now, all I had to do was solder some wire from the jack to the router.
After looking through the documents, I saw that the plug has outputs as shown here.Â
The Jack then needed to be wired thusly.
As a reminder here is where the Ground/TXD and RXD connections are on the router.
You can also find more information about these connections here.
Once finished, the router now looks like this.
Now all I have to do is snap the cover back on and if I ever need to debrick my router again, I simply plug in and go!
If you need more info on what programs, connections or step by step directions on debricking your WNR3500L router seehere.
This hack saved my butt, my router had NO headers and as such was easier to solder in place this way, thank you so much for sharing, it worked exactly as advertised!
Does anyone know what the TX and RX connect to in a normal usb pinout? I have all the components to make the cable above for a lot less $ than buying the actual manufactured cable. The usb pinouts are +5 vcd, data -, data + and ground. I'm guessing that the TX and RX connect to the two data wires but I'm not sure which is which.
Bitbyter, no they do not. You cannot directly connect a USB cable. You need a chip to convert USB to serial, and then also to the correct voltage levels.