Asus P8B-C/4L User Manual page 55

7. Serial General Purpose Input/Output connector (6-1 pin SGPIO1)
This connector is used for the SGPIO peripherals for the Intel Rapid Storage
Technology RAID SATA LED.
8. Serial General Purpose Input/Output connectors
(8-1 pin SGPIO2/3, P8B-C/SAS/2L, P8B-C/SAS/4L only )
These connectors are used for the SAS chip SGPIO interface that controls
the LED pattern generation, device information and general purpose data.
ASUS P8B-C series 2-37