There is a 6 pad debug interface on the back of the blade.
The pin out for rs232 is below.
1=closest to SD slot. 1 2 3 4 5 6 Where 3 = TX 2.8V 5 = RX 2.8V 6 = GND
I will try to get some sort of connector working tomorrow and take some photos. The serial port is disabled in the kernel by default, so a kernel needs to be compiled to use it (or the kernel in my latest gingerbread rom has it enabled).
More info to come...
Edit. Updated pin out.
Edit. Now with pics.
This is my setup. There are many ways this could be done, this is only one example.
What you will need
Soldering iron. You want something with a fairly small tip.
A little bit of solder
Wire. I used 30ag. You want something small and try to keep it short.
Hot melt glue gun. This is optional, but these things are great for modding hardware.
3.3V RS232 adapter. I used the FT232R board below. They are available from sparkfun.com. There are many other solutions for this. If you want to do it really cheap a MAX232 should work.
Do not hook the phone up directly to a PC RS232 port. PC ports us higher voltage and may seriously damage your phone.
ft232r_small.JPG 135.15KB 169 downloads
The points to connect
back2_small.JPG 263.13KB 169 downloads
back1_small.JPG 89.25KB 183 downloads
GND = Green
RX = Blue
TX = Red
PHONE <-> RS232 adapter GND - GND RX - TX TX - RX
Use some flux on the area to be soldered.
Put a little solder on the points before trying to attach the wires.
prep1_small.JPG 105.63KB 128 downloads
When you solder the wires on have them running toward the sd card side of the phone. I initially soldered them facing towards the sim card and then found I couldnt easily put a card in.
I didn't get any decent photos of it soldered once complete, so here is one with GND connect to the worng point. DONT do it this way.
solder_wrong_small.JPG 104.39KB 160 downloads
Once its all done use a bit of glue to hold the wires in place.
finished_small.JPG 123.88KB 172 downloads
Edited by Tom G, 19 December 2010 - 01:56 PM.