Dell PowerEdge R530 Owner's Manual page 146

5 SAS B connector
Figure 78. Cabling diagram of the hard drive backplane using the onboard controller
1 system board
3 SATA B cable connector on system board
5 hard drive backplane
7 signal cable connector on backplane
146 Installing and removing system components
6 hard drive connectors (8)
2 SATA A cable connector on system board
4 signal cable connector on system board
6 SAS B cable connector on backplane
8 SAS A cable connector on backplane