Cpu_Fan1, Sys_Fan1~3: Fan Connectors; Jcom1: Serial Port Connector - MSI B450M MORTAR TITANIUM Quick Start Manual

CPU_FAN1, SYS_FAN1~3: Fan Connectors

Fan connectors can be classified as PWM (Pulse Width Modulation) Mode or DC Mode.
PWM Mode fan connectors provide constant 12V output and adjust fan speed with
speed control signal. DC Mode fan connectors control fan speed by changing voltage.
When you plug a 3-pin (Non-PWM) fan to a fan connector in PWM mode, the fan speed
will always maintain at 100%, which might create a lot of noise. You can follow the
instruction below to adjust the fan connector to PWM or DC Mode. However, with auto-
detection mode fan connectors, the system will auto detect the fan mode.
Pin definition of fan connectors
PWM Mode pin definition
1 Ground 2
3 Sense 4
Important
You can switch between PWM mode and DC mode and adjust fan speed in BIOS >
y
HARDWARE MONITOR.
Make sure fans are working properly after switching the PWM/ DC mode.
y

JCOM1: Serial Port Connector

This connector allows you to connect the optional serial port with bracket.
Automatically detect mode fan connector
Default DC Mode fan connectors
1
SYS_FAN1/ SYS_FAN2
+12V
Speed Control Signal
1
3
5
7
9
1
CPU_FAN1
DC Mode pin definition
1 Ground 2
3 Sense 4
2 10
1
9
DCD 2
SOUT 4
Ground 6
RTS 8
RI 10
1
SYS_FAN3
Voltage Control
NC
SIN
DTR
DSR
CTS
No Pin
Overview of Components
19