https://www.pjrc.com/teensy/49-teensy.rules
Teensy directly from USB to Linux USB
device: ttyACM0
another way
Teensy HW UART through Serial-to-USB converter
device: ttyUSB0
Stream using cat /dev/ttyXX won't work unless the port has been configured to the baud rate.
A direct way is to use Minicom or Screen as a terminal.
For Screen (very unconventional interface, but we only need start and quit cmds),
screen /dev/ttyACM0 115200
data streams here
^ka y to exit.
