Serial Console Access
Gaining local access via serial console to your router is helpful in many situations. Simple examples are:
- debugging a somehow non-functional firmware image
- fixing/debugging a misconfigured networking setup
- flashing certain devices (Netgear WGT634U)
You might think modding serial access is hard work and should be done only by experts. Well, you might be wrong. This article aims at showing how simple things can be.
Dependencies
Things you need to have at hand to do this mod:
- soldering iron and solder
- a set of stereo jack plugs
- a supported usb cell phone data cable (e.g. one for siemens sl55 and friends)
- the correct pinout for the cable mentioned above
- the pinout for the serial connector of your device
- a few inches of isolated wire
- for some devices a multi-pin connector
- if you want to keep everything modular, also a female connector
Howto
So let's finally start:
First, choose a nice place for installing the female connector at the case:
Mark the position at the case, then make sure you got enough power to both drill the hole and prevent your hands from shaking too much when actually soldering everything together. For me, a hot coup of noodle soup did the job:
Ok, time for drilling some holes. First remove all electronics from the case, as it's known to becoming instable after being borne up:
Next, take your weapon of choice and start with happy drilling. I chose a pair of scissors for the job:
Of course, you may use better tools than I did. Just make sure the result looks as well as mine:
To connect the plug to the pins on the board, you need the isolated wire. Ever bought an unsupported data cable? This is how to recycle it:
Time for a short conversation with Mr. Soldering Iron:
Soldering part 1:
Some isolating tape is always a good choice to prevent short circuits:
Before going any further, make sure Mr. Beeper says everything is fine even after applying the isolating tape:
If you didn't create any internal short circuits while trying to prevent external ones, go on with soldering part 2:
Finally, fit everything together into the case:
If you did everything right, your result should look like follows:
Also note the already assembled male connector (sorry, undocumented) in the picture above.
Hints
Be careful when soldering isolated wire. although you might still be able to hold the isolation, the wire itself is getting very soon very hot. This may lead to wires melted together short circuiting everything, so be aware that Mr. Beeper is always a good friend.
When nothing seems to be working even after checking for short circuits, first check your serial console setup, then certain hardware quirks before consulting Mr. Solder Iron again (like I did). Especially the hardware used for this Howto only works correctly when powered up without serial console connector attached. You can plug in the stereo jack after about a second or two and everything is fine when nothing was before.
