Connection Settings
Settings → Connection configures how AxioCNC talks to your CNC controller over the serial port.
Port
Port — Serial port for the controller.
- Linux / Pi: e.g.
/dev/ttyUSB0,/dev/ttyACM0. Use Refresh to rescan. - Windows: e.g.
COM3,COM4. - macOS: e.g.
/dev/cu.usbserial-*,/dev/cu.usbmodem*.
If the port is missing, connect the controller, install drivers if needed, and click Refresh. On Linux/Pi, ensure your user is in the dialout group.
Baud rate
Baud rate — Communication speed. 115200 is common for Grbl. Use the value your firmware expects (e.g. 9600, 115200, 250000).
Controller type
Controller type — Grbl, Marlin, Smoothie, or TinyG / g2core. Must match your board’s firmware.
Serial line controls
- Set DTR line status upon opening — Usually on. Turn off only if your board requires it.
- Set RTS line status upon opening — Usually on. Turn off only if your board requires it.
- Use RTS/CTS flow control — Off unless your controller and wiring use hardware flow control.
Connect automatically
Connect automatically — When on, AxioCNC connects to the selected port on startup. When off, you connect manually from the main UI.
Test connection
Test connection — Opens the port, checks communication, then closes it. Use this to verify port, baud, and controller type before connecting for real. The result (success or error message) is shown next to the button.