About BR305 - nothing special. I just found an article about psp serial and soldered a level-converter.
Here we go:
http://nil.rpc1.org/psp/remote.html
Then I found a pinout of BR305 (in russian) - the ps/2 like connector is from BR305
http://www.gpshome.ru/support/connectors/
Actually, the most tricky part was to determine signal level of BR305 and decide, do I need max3232 circuit, or not... There was no data about signal levels. It may be 3v-level rs-232 or something else - i don't have an oscilloscope at home =).
After a day of diggin google and forums I found an answer on www.gpshome.ru - it was definetely +-12volts RS-232.
First of all I soldered DIY cable for ordinal PC serial port. I have a thinkpad for weird hardware expirements =).
Cable worked. That was good news.
After that I bougt soj variant of max3232. The first thought was: "Uh oh - I should drink less coffee and beer to reduce handshaking" =).
Finally, i made a simple circuit board for a chip. Nothing special - just cut some parallel lines on textolite =).
Then... Soldering.. Testing. Mixed cables.. No power on chip, mixed cables again, burned hands... I 'm not really expierenced in smd soldering =)).
Finally, I got nemea strings in lua serial port echo =).
My girlfriend wanted to kill me at 2:00 am at night, because I was singing halleluja at wake her up =).
Later I downloaded all this development stuff for psp and grepped for "38400" in source code. Just changed it for "4800", kxploited new eboot and... Got NEMEA sentences on this "Green" app =).
You know all the rest.
About Moscow. I'm living permanently at "Red Gates" metro station ("Lermontovskaya"), and staying at my girlfriend's house for several days in a week an "Schelkovskaya" metro station.
My university is located at Taganka =). (I've graduated already).
Back to hardware. Important tips! I got an external PSP battery and I'm using it to power up GPS device !
Now I'm solving a problem to attach a little box with circut to psp itself and not to spoil the case =).
