Asus Z9PE-D16 - Manual (Page 48)

2-30 Chapter 2: Hardware information
6. Serial General Purpose Input/Output connectors
(8-1 pin PSGPIO 1/2, ISGPIO 1/2, SGPIO1)
The SGPIO 1 connectors are used for the Intel Rapid Storage Technology
Enterprise SGPIO interface that controls the LED pattern generation, device
information and general purpose data.
The PSGPIO 1/2 connectors are used for PIKE card.
The ISGPIO 1/2 connectors are used for ASRK module.
7. Serial port connectors (10-1 pin COM1/COM2)
These connectors are for the serial (COM) ports. Connect the serial port
module cable to one of these connectors, then install the module to a slot
opening at the back of the system chassis.