A serial multiplexer module for server management includes a first, a second and a third switching devices in circuit connection with a baseboard management controller, a serial transceiver and an input/output controller respectively. Each of the switching devices includes respectively four simplex sub-switches. The simplex sub-switches are controlled to be switched on/off directly/indirectly by a first control signal and/or a second control signal transmitted from the baseboard management controller, thereby enabling and monitoring the communication between the baseboard management controller, the input/output controller and the serial transceiver.