Dell EMC PowerEdge R740 Installation And Service Manual page 162

Figure 119. Cable routing – 16 x 2.5 inch drive backplane with mini PERC
1 backplane
3 backplane power cable (BP: BP1 to MB: BP1)
5 system board
7 SAS cable (BP: BP SAS A0, BP SAS BO to MB: J_STORAGE1)
162 Installing and removing system components
2 backplane expander
4 backplane signal cable (BP: BPSIG1 to MB: BPSIG1)
6 mini PERC