Dell PowerEdge 6400 Manual page 6

4 SCSI Backplane Option
1 Ultra3 SCSI cable connector (SCSIA)
2 Ultra3 SCSI cable connector (SCSIB)
3 Cooling fan power cable connector (FAN)
4 Power connector (POWER)
5 System-board data cable connector (PLANAR)
13. Connect the power cable labeled "HD-B/P" to the connector labeled "POWER" on
the backplane board.
14. Connect a SCSI cable from the connector labeled "SCSIA" on the backplane board
to the connector labeled "PRIMARY SCSIA" on the system board, or to a SCSI
host adapter card.
15. If you want to operate the backplane in a split 2 x 4 configuration, connect a SCSI
cable from the connector labeled "SCSIB" on the backplane board to the second
Ultra3 SCSI connector on the system board, or to a SCSI host adapter card.
NOTES: When the 2 x 4 SCSI backplane is cabled to two SCSI host adapter
cards, the SCSI host adapter cabled to the 2 x 4 backplane's SCSIA connector will
control the four top hard-disk drives of a rack-mounted system (or the four left-
most hard-disk drives of an upright free-standing system) with SCSI IDs 0, 1, 2,
and 3; and will control the four bottom hard-disk drives of a rack-mounted system
(or the four rightmost hard-disk drives of an upright free-standing system) with
SCSI IDs 4, 5, 8, and 9.