Figure 444. Cable routing to onboard SATA connectors
From To
1  Backplane 1: SAS 0, SAS 1 Onboard: SATA 0, SATA 1
2  Backplane 1: SAS 2 Onboard: SATA 2
Middle backplane cable routing
Connections between connectors: 
1  ↔  1 ,  2  ↔  2 ,  3  ↔  3 , ...  n  ↔  n
428 ThinkSystem SR650 V3 User Guide