** BEWARE ** USE THIS INFORMATION AT YOUR OWN RISK **
Looking at the 4-pin connector of my GP standard, from left to right:
2: Serial out (from the plug)
3: Serial in (to the plug)
I successfully connected to the console by using a MAX3232 level converter, in order to be able to interface to the RS232 port on my computer. I used the reference design found on the datasheet. Serial port configuration is 115200, 8, N,1, no handshake.