Middle and rear backplanes: 4 x 3.5-inch SAS/SATA + 4 x 3.5-inch SAS/SATA
This topic provides cable routing information for the 12 x 3.5-inch Anybay configuration with a 4 x 3.5-inch 
SAS/SATA middle drive cage and a 4 x 3.5-inch SAS/SATA rear drive cage.
One 32i RAID/HBA adapter + onboard connectors
From To
Backplane 1: SAS 0, SAS 1 32i RAID adapter on PCIe slot 3: 
•  C0
Backplane 1: SAS 2
•  C1
Backplane 4: SAS
Backplane 5: SAS
•  C2
Backplane 1: NVMe 0-1, 2-3, 4-5, 6-7 Onboard: PCIe 1, 2, 3, 4
Backplane 1: NVMe 8-9, 10-11 Onboard: PCIe 5, PCIe 6
Connections between connectors: 
1  ↔  1 ,  2  ↔  2 ,  3  ↔  3 , ...  n  ↔  n
Figure 144. SAS/SATA cable routing
Figure 145. NVMe cable routing
Chapter 3. Internal cable routing 183