Asus Z9PA-U8 - Manual (Page 52)

2-32 Chapter 2: Hardware information
4. USB connectors (10-1 pin USB34, USB56; A-Type USB10)
These connectors are for USB 2.0 ports. Connect the USB module cables to
connectors USB34 and USB56, then install the modules to a slot opening at
the back of the system chassis. These USB connectors comply with USB 2.0
specification that supports up to 480 Mbps connection speed.
5. Serial port connector (10-1 pin 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.