If you decided to mod your wrt54gl router and turn it into one of the most capable routers for soho network, probably the first mod you should start with is adding serial interface to it. Why? Because when you do the other mods (like adding SD reader, turning into robot, adding leds etc) you definitely send the router into the brick state. And the best way to unbrick it is to look at the router’s console output. The entire operation is very easy and should not take longer then 1 hour. Here is how to do this:
- Open the router. This video shows how.
- Locate the 10-pin connector on the board. It provides two serial interfaces and we will need one of them (serial console). You can similarly use the other one to control other devices via serial interface, but this is a separate topic.
- Get an RS232 adapter. For instance this one.
- If your computer doesn’t have com port, and has USB then get an adapter. For instance this one. If your computer doesn’t have USB ports, get another computer. Any computer with either USB or serial interface would work.
- Connect pins from the router board to pins on the RS232 adapter as following: 4->”TX”, 6->”RX”, 10->”-“, 2->”+”. Use either soldering iron or standard F/F connectors like this ones.
- Connect the RS232 adapter to the computer (via USB-Serial adapter if necessary), connect the RS232 adapter to the router board, turn everything on and check that the leds on the RS232 adapter lit appropriately (refer to the adapter manual to find out what’s appropriate)
- Turn everything off, start your favorite terminal program (for windows users that’s possibly hyperterm), configure it as 115200 8N1 (115200 bps speed, 8 data bits, no parity, 1 stop bit) and power the router on again.
Now you should be able to see what’s happening in the router’s brain. Based on your linux experience you can diagnose what’s going wrong and try to fix it using full access to the router you just got.
In addition to 10-pin serial connector the router also provides 12-pin JTAG connector you can use to bring the router to live in situations when serial port is dead. But this is completely different story and I hope you will never need JTAG (for this purpose).
Now you have serial interface added to your router. If you want to give it even more capabilities take a look at the most hacked router in the world ever :)