Asus ESC500 G2 - Manual (Page 58)

Chapter 3: Motherboard information 3-16
6. IEEE 1394a port connector (10-1 pin IE1394_2)
This connector is for an IEEE 1394a port. Connect the IEEE 1394a module
cable to this connector, then install the module to a slot opening at the back
of the system chassis.
Never connect a USB cable to the IEEE 1394a connector. Doing so will damage
the motherboard!
The IEEE 1394a module is purchased separately.
7. Digital audio connector (4-1 pin SPDIF_OUT)
This connector is for an additional Sony/Philips Digital Interface (S/PDIF)
port. Connect the S/PDIF Out module cable to this connector, then install the
module to a slot opening at the back of the system chassis.
The S/PDIF module is purchased separately.