Asus M2N-SLI Deluxe - Manual (Page 56)

2-2 Chapter 2: Hardware information
13. Digital audio connector (4-1 pin SPDIF_OUT)
This connector is for an additional Sony/Philips Digital Interface (S/PDIF)
port(s). 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.
M2N-SLI DELUXE Digital Audio Connector
+5
V
SPDIFOU
T
GN
D
SPDIF_OUT
R
M2N-SLI DELUXE