Asus M4A78-EM/1394 - Manual (Page 34)

1.10.2 Internal connectors
1. Serial port connector (10-1 pin COM1)
The connector is for a serial (COM) port. Connect the serial port module cable to the
connector, then install the module to a slot opening at the back of the system chassis.
The serial port bracket (COM1) is purchased separately.
2. Power, CPU, and chassis fan connectors (3-pin PWR_FAN, 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.
Only the CPU fan supports the ASUS Q-Fan feature.
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.
Chapter 1: Product introduction 1-22