Apple ColorSync Display - Manual (Page 66)

Display cable specifications
m 15-pin miniature D-type connector
Pin Signal
1 Red video ground
2 Red video
3 Not used
4 ID 1/DDC RTN
5 Green video
6 Green video ground
7 ID 2/DDC SCL
8 DDC 5V (not used for 17")
9 Blue video
10 ID 3/DDC SDA
11 Vertical Sync return
12 Vertical Sync
13 Blue video ground
14 Horizontal Sync return
15 Horizontal Sync
Shell Shield ground
8 7 6 5 4 3 2 1
15 14 13 12 11 10 9
68 Appendix B