List serial ports
dmesg | grep ttyGPIO serial port is /dev/ttyAMA0
USB when added usually has a USB in its name, e.g. /dev/ttyUSB0
List just USB serial ports
dmesg | grep ttyUSBList all ports
ls /dev/tty*Assigning a fixed name to a USB serial port
https://www.freva.com/assign-fixed-usb-port-names-to-your-raspberry-pi/