Asus P5KR Manual page 59

9. CPU, chassis, and power fan connectors
(4-pin CPU_FAN, 3-pin CHA_FAN1, 3-pin CHA_FAN2, 3-pin PWR_FAN)
The fan connectors support cooling fans of 350 mA~2000 mA (24 W max.)
or a total of 1 A~7 A (84 W max.) at +12V. Connect the fan cables to the fan
connectors on the motherboard, making sure 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!
P5KR
P5KR Fan connectors
Only the CPU-FAN and CHA-FAN 1-2 connectors support the ASUS Q-FAN 2
feature.
10. Serial port connector (10-1 pin COM1)
This connector is for a serial (COM) port. Connect the serial port module
cable to this connector, then install the module to a slot opening at the back
of the system chassis.
P5KR
P5KR Fan connectors
The serial port module is purchased separately.
ASUS P5KR
CPU_FAN CHA_FAN1
PWR_FAN CHA_FAN2
GND
+12V
Rotation
CPU_FAN CHA_FAN1
PWR_FAN CHA_FAN2
GND
+12V
Rotation
2-35