IMHO best is good old screen
screen /dev/ttyUSB0 115200
Problem can appear after device (e.g. ttyUSB0) is created only for root.
udev rule has to be set. Add new file e.g. 99-local.rules to /etc/udev/rules.d directory:
# Locally defined rules.
# Give world read/write access to ttyS* and ttyUSB* serial devices
KERNEL=="tty[A-Z]*", GROUP="uucp", MODE="0666"
To see if usb to serial converter is working in linux "lsusb" can be used.
Access to usb possible due to libusb.