Rear backplane: 4 x 2.5-inch SAS/SATA
The following shows the cable connections for a rear 4 x 2.5-inch SAS/SATA backplane if installed.
From To
Backplane 4: SAS 32i RAID adapter on PCIe slot 2: C3
Backplane 4: PWR Riser 1: PWR1, PWR2
Figure 112. Cable routing for the rear 4 x 2.5-inch SAS/SATA backplane
156 ThinkSystem SR650 V2Maintenance Manual