IBM 6648 - Manual (Page 80)

v Pin 1 is at the top.
v Pin 2 is in the middle.
v Pin 3 is at the bottom.
To enable Ethernet, jumper pins 1-2. To disable Ethernet, jumper pins 2-3.
1 PCI slot 1 3 Ethernet disable jumper
2 PCI slot 2
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Hardware Maintenance Manual: IBM NetVista Computer Types 6058, 6059, 6269, 6568, 6569, 6578, 6579, 6648,
6649