
I'm not really an electronics kinda persion, but I managed to bodge this together and it works quite nicely with PSXSerial,
The R3 was the first board not to use an FTDI chip, so you can't solder directly to those pads, but pins 0 & 1 on some models still work nicely as a passthrough if you connect Reset to Ground; so no need for the SoftSerial library which is really too slow for 115200.
8K Seems about right for the resistor(s) - the ohmmeter is reading 7.4ish - too far either way and things don't work so well, but lemme know if the image needs changing ^^