Upgraded pyserial to v 3.0.1 list available COM ports: $ python -m serial.tools.list_ports /dev/ttyAMA0 /dev/ttyUSB0 /dev/ttyUSB1 3 ports found running $ python -m serial.tools.miniterm /dev/ttyUSB0 opens miniterm: --- Miniterm on /dev/ttyUSB0 9600,8,N,1 --- --- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H --- at OK works fine.