In only have a STE, the information about the 520ST having GND connected on Pin 8 is based on this pinout:
http://info-coach.fr/atari/hardware/int ... _connector
Since it is obviously wrong I corrected it.
I did a little research, and found that many sites show this wrong pin out. This page did a little research where this mistake actually came from, and it seems to be based on the Book "The Concise Atari ST Programmer's Reference Guide" by Katherine D. Peel, ISBN 1 85181 017 X.