IBM 704 - Manual (Page 307)

Changing Jumper and Switch Settings
12 Not used
13 Multiprocessing-bus connector (not used)
14 Fan 3 connector (outer chassis fan, upper)
15 Fan 4 connector (outer chassis fan, lower)
16 Hard disk drive LED 2 connector
17 SCSI channels 1 (right) and 2 (left) connectors
18 EISA slots 1–4 for adapters (slot 1 toward top, slot 4
toward bottom)
19 PCI slots 1–6 for adapters (slot 1 toward top, slot 6 toward
bottom: Bus 0 = slots 1–3; Bus 1 = slots 4–6)
2 Configuration switches and jumpers
21 Real-time clock connector
22 Video memory DRAM connector
23 VGA monitor connector
24 Parallel-port connector
25 Serial-port connectors A (COM1) and B (COM2)
26 PS/2-compatible keyboard and mouse connectors
Changing Jumper and Switch Settings
Jumpers and switches are used to define configuration values on the
system board, backplanes, adapters, and other devices. Refer to the
documentation that comes with the devices for specific information
about the appropriate jumper settings.
This section provides information on:
Changing a jumper setting
Setting the SCSI ID on a device or backplane
Setting the system-board configuration jumpers
Changing the system-board configuration switches
Appendix A. Server Records 289