The CLI discovers a V5 brain through the operating system’s serial devices and supports Linux, macOS, and Windows. The serial library uses the browser’s Web Serial API instead, so it works wherever that API is implemented.

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Before connecting

  • Turn on the brain and connect it directly over USB.
  • Use a data-capable USB cable.
  • Close VEXcode and other tools that may already own the port.
  • On Linux, make sure your user can access the relevant /dev/tty* device.
  • On Windows, let the brain finish enumerating so its COM port appears in Device Manager before running a hardware command.
  • In a browser, use a secure context and grant device permission when prompted.
Only one process should control the serial port at a time. A permission or “port already open” error usually means another process owns it.

CLI troubleshooting

Serial troubleshooting

Device connections - v5x