Asus M2A74-AM - Manual (Page 35)

9. Digital audio connector (4-1 pin SPDIF_OUT)
This connector is for an additional Sony/Philips Digital Interface (S/PDIF) port.
Ensure that the audio device of Sound playback is VIA High Definition Audio (the name
may be different based on the OS). Go to Start > Control Panel > Sounds and Audio
Devices > Sound Playback to configure the setting.
The S/PDIF module is purchased separately.
10. CPU and chassis fan connectors (4-pin CPU_FAN, 3-pin CHA_FAN)
The fan connectors support cooling fans of 350mA~740mA (8.88W max.) or a total of
1A~2.22A (26.64W max.) at +12V. Connect the fan cables to the fan connectors on the
motherboard, ensuring that the black wire of each cable matches the ground pin of the
connector.
DO NOT forget to connect the fan cables to the fan connectors. Insufficient air flow inside
the system may damage the motherboard components. These are not jumpers! DO NOT
place jumper caps on the fan connectors.
Only the CPU fan supports the ASUS Q-Fan feature.
ASUS M2A74-AM 1-25