For those interested, I just found this info in Google Groups:
In the industry, there are 2 wiring schemes for these pigtails. IBM/DTK
wiring and Everex wiring, as they are called. IBM/DTK wires the ribbon
straight into the DB9, whereas Everex wiring matches up the pin #s:
DTK/IBM
IDC/ribbon....DB9
1 . . . . . . . . . 1
2 . . . . . . . . . 6
3 . . . . . . . . . 2
4 . . . . . . . . . 7
5 . . . . . . . . . 3
6 . . . . . . . . . 8
7 . . . . . . . . . 4
8 . . . . . . . . . 9
9 . . . . . . . . . 5
Everex
IDC/ribbon DB9
1 . . . . . . . . . 1
2 . . . . . . . . . 2
3 . . . . . . . . . 3
4 . . . . . . . . . 4
5 . . . . . . . . . 5
6 . . . . . . . . . 6
7 . . . . . . . . . 7
8 . . . . . . . . . 8
9 . . . . . . . . . 9
Unfortunately, the manual for the P4P800 does not list RS-232 signals associated with the header on the motherboard, so it is not possible to determine which wiring scheme is correct... :disgust: