Middle backplanes: 8 x 2.5-inch NVMe
This topic provides cable routing information for the 12 x 3.5-inch SAS/SATA server model with an 8 x 2.5- 
inch NVMe middle drive cage.
•  “Front backplane: 12 x 3.5-inch SAS/SATA” on page 176
•  “Middle backplanes: 8 x 2.5-inch NVMe” on page 177
Front backplane: 12 x 3.5-inch SAS/SATA
The following shows the cable connections for the 12 x 3.5-inch SAS/SATA configuration with one 16i RAID/ 
HBA adapter.
From To
Backplane 1: SAS 0, SAS 1 16i RAID/HBA adapter on PCIe slot 2:
•  Gen 3: C0C1
•  Gen 4: C0
Backplane 1: SAS 2
•  Gen 3: C2C3
•  Gen 4: C1
Connections between connectors: 
1  ↔  1 ,  2  ↔  2 ,  3  ↔  3 , ...  n  ↔  n
Figure 134. Cable routing for the 12 x 3.5-inch SAS/SATA configuration with one 16i RAID/HBA adapter
176 ThinkSystem SR650 V2Maintenance Manual