Asus P9D-MH/SAS/10G-DUAL - Manual (Page 58)

2-38 Chapter 2: Hardware information
9. Power Supply SMBus connector (5-pin PSUSMB1)
This connector allows you to connect SMBus (System Management Bus) to the power
supply unit to read PSU information. Devices communicate with an SMBus host and/or
other SMBus devices using the SMBus interface.
This connector functions only when you install the ASUS ASMB7.
10. Hard disk activity connector (4-pin HDLED1)
This LED connector is for the storage add-on card cable connected to the SATA or SAS
add-on card. The read or write activities of any device connected to the SATA or SAS
add-on card causes the front panel LED to light up.