Some latest versions of the Linux kernel come preinstalled with a driver module for Moxa’s multiport serial board (MSB). The driver will load automatically when you install a Moxa PCI MSB on your system. When you run the lsmod command, the driver is listed as mxser_new. However, you may not be able to access the serial ports on the MSB using this preinstalled driver. To install the latest driver from Moxa, you must first remove the preinstalled driver. Otherwise, you will see two modules—mxser and mxser_new—and the Moxa driver will not work properly.

Use the following commands to remove the existing driver module from your system.

# rmmod mxser_new
# rm –f /lib/modules/2.6.xx-xx/kernel/drivers/char/mxser_new.ko

After removing the preinstalled driver, follow the instructions below to install the latest driver from Moxa.

1. Extract the driver files into the mxser directory.
2. Install the driver in the mxser directory.
   # make clean; make install
3. Load the driver module.
   # modprobe mxser
4. Use the lsmod command to check if the driver is installed
   # lsmod | grep mxser