In order to get USB to serial converters working in linux with minicom, you must chmod give non-root users the ability to access the USB to serial device.
Install minicom using the normal methods for your distro. Then start minicom as root.
set to 9600 8N1
save settings and default and exit minicom.
Next give normal users the ability to use the USB serial port.
chmod a+rw /dev/ttyUSB0
exit to a normal user shell and try to start minicom