I have been traying to run the command $ screen /dev/ttyACM0 57600 8N1 , but it shows very rare symbols (as you can see in the picture) Do you know how can i fix this problem???
Im not using the FTDI, i’m just using the usb cable, is it necessary to use the FTDI ???
As @jinchengde said, PX4 starts a mavlink instance on the USB port. You can use the shell via this (or any other) mavlink connection with the mavlink shell.
Note that the mavlink shell is also available in QGC.