Asus RS520-X5/PS8 - Manual (Page 52)

4-10 Chapter 4: Motherboard information
5. SAS connectors
This motherboard comes with eight blue Serial Attached SCSI (SAS)
connectors, the next-generation storage technology that supports both Serial
Attached SCSI and Serial ATA (SATA). Each connector supports one device.
To connect the SAS cable:
Plug in the SAS cable to the
SAS1-8 connector until the cable
snaps in place.
6. SAS LSI1068 ports LED connector (18-1 pin SASLED1)
This connector is for the front panel LED port indicator that shows the SAS
HDD status.