Asus P1-P5945GC User Manual page 54

7. Back audio connector (20-1 pin Back_Audio Connector)
Back_Audio Connector
We recommend that you connect a high-definition front panel audio
module to this connector to avail of the motherboard's high-definition
audio capability.
8. 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 module cable to this connector,
then install the module to a slot opening at the back of the system
chassis.
Digital Audio Connector
The S/PDIF module is purchased separately.
ASUS P1/P2-P5945GC
R
R
SPDIF_OUT module
BACK_AUDIO
SPDIF_OUT
4-9