Dell PowerVault DP500 - Manual (Page 61)

Figure 6 -3 and Figure 6 -4 show the location of the connectors on the three SAS backplane board options.
Figure 6-3. SAS Backplane Board Components: 3.5-inch x6 Option
Figure 6-4. SAS Backplane Board Components: 3.5-inch x4 Option
Sideplane Board Connectors
See Figure 6 -5 for the location and description of connectors on the sideplane board.
Figure 6-5. Sideplane Board Connectors
1 drive 0 (SASDRV0) 2 primary SAS (SAS_A)
3 drive 2 (SASDRV2) 4 optical drive power (CD_PWR)
5 secondary SAS (SAS_B) 6 drive 4 (SASDRV4)
7 drive 5 (SASDRV5) 8 drive 3 (SASDRV3)
9 drive 1 (SASDRV1) 10 backplane power (BP_PWR)
1 drive 0 (SASDRV0) 2 SAS (SAS_A)
3 tape drive power connector (J_TBU_PWR) 4 drive 2 (SASDRV2)
5 drive 3 (SASDRV3) 6 drive 1 (SASDRV1)
7 backplane power (J_BP_PWR)