/* Void Main's Wifi Tips */

{ Wifi/OpenWrt Tips(); } else { main(); }
ยป Void Main's Serial Port Mods and Console Cables
#include <stddisclaimer.h>

When might you use this tip?
- You need console access to your router and/or other serial connectivity

Pros: Cheap and Easy.

Cons: Not all WRT units have serial ports.

Tools/parts Required: Soldering iron. Max232 kit and/or CA-42 or DKU-5 USB cable.

Let us begin:

NOTE: Click on the thumbnail images in this tip to zoom in on the image.

If you just want a console cable the easiest and cheapeast way to go is to purchase a Nokia USB phone cable. There are two models that work, a DKU-5 or CA-42. I have read that there are different chipsets in these cables but I believe you should be fairly safe with the CA-42. I have one of each that I purchased from Amazon for less than $2 each. When I plug them in to my Linux machine they both are detected as "pl2303" in the dmesg output and show up as /dev/ttyUSB0.

In the picture below you can see the DKU-5 cable that I have already modified. I soldered header pins onto the WRT54G (this one is a WRT54G v2.2), cut the end off the DKU-5 and connected a 10 pin header. Now all you have to do is plug one end of the cable onto the board and plug the other end into your PC and load up a communications program (I use minicom in Linux). Set the speed to 115,200,8,N,1 using /dev/ttyUSB0. Now boot your router and you should see console messages. When the router is booted just press ENTER to go to the console shell.


Now for the details. The pinout on the serial connector on the picture above:

Pin  1: 3.3V        Pin  2: 3.3V
Pin  3: Tx (ttyS1)  Pin  4: Tx (ttyS0)
Pin  5: Rx (ttyS1)  Pin  6: Rx (ttyS0)
Pin  7: NC          Pin  8: NC
Pin  9: GND         Pin 10: GND

Only 3 wires are needed for the console cable. My CA-42 only had 3 wires in it and the DKU-5 had 4 wires. The 3 needed wires will connect to pins 4 (Tx), 6 (Rx), and 10 (GND) on the board. Cut the end off of the CA-42/DKU-5 cable and use a multimeter to find what color wire is associated with pins 5 (Rx), 6 (Tx), and 7 (GND) in the picture below. Connect whatever color wire associated with pin 5 on the cable to pin 6 on a 10 pin header plug. Connect whatever color wire associated with pin 6 on the cable to pin 4 on the 10 pin header plug. Connect whatever color wire is associated with pin 7 on the cable to pin 10 on the 10 pin header plug. That's it.


In the above picture I didn't have an extra 10 pin header plug lying around but I did have a bunch of old IDE cables so I just took a pair of side cutters and cut off the last 10 pins to make a 10 pin header. I removed the IDE cable and connected the 3 wires from the Nokia cable to the appropriate pins and then put a little hot glue on it for support.

Now, if you want to be able to plug it into a regular serial port you'll have to go through a little more work. It might be easier to just point you to Jim Buzbee's excellent instructions. I created a Frankenstein version out of an AD233DK dual port serial kit that will allow me to connect any type of connector. I can connect to the console port (ttyS0) via 9 pin serial, RJ45, or USB. The second serial port (ttyS1) has both a male and female 9 pin. Don't ask me why, I just got carried away.


CA-42/DKU-5 cables can be had for under 2 bucks on Amazon

Just ran across this site which looks to have a lot of good info and he also used a Micro SD card.

Further Reading:
Linksys GPL Firmware page (Thank you Linksys and thank you Richard Stallman (GPL)!!)
OpenWRT Web Site (my wireless web server runs it)
My revival thread (Thanks Jim!)
My wireless web server thread
Jim Buzbee's Linux on WRT54G page
Seattle Wireless WRT54G page
French Version of This (Thanks m.! Forum Topic)
P.S. SVEASOFT and Windows are not supported here.

Have fun!


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