Lenovo ThinkSystem SR650 V2 - Page 164

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 CFF expander: C3
Backplane 4: PWR Riser 1: PWR1, PWR2
Figure 109. Cable routing for rear 4 x 2.5-inch SAS/SATA backplane
154 ThinkSystem SR650 V2Maintenance Manual