USB Connection Web Serial
USB mode connects the browser directly to a printer control board through Web Serial. It is useful when the printer is not on the network or when you need a simple G-code transport path.
- Chromium browser: Chrome, Edge, Brave, Arc, Opera, or similar.
- Page served over HTTPS or
http://localhost. - USB data cable, not a charge-only cable.
- Printer board powered on.
- No other application holding the serial port.
Firefox and Safari do not implement Web Serial.
Open the printer's Connection settings, switch to USB, then click Select USB Port.
The browser chooser may show the board vendor, USB chip, or generic serial device name. After permission is granted, Cindr3D stores the USB vendor/product identity for that browser origin.
Use Change Port to switch printers and Clear to release the saved permission.
The baud rate must match the firmware.
| Firmware | Common baud |
|---|---|
| Marlin | 115200 or 250000 |
| RepRapFirmware | 115200 |
| Klipper USB | 250000 |
Garbled output or no response to M115 usually means the baud rate is wrong.
Use the USB diagnostic console before committing to a full connection.
Useful checks:
-
M115: firmware identity. -
M105: temperatures. -
M119: endstop states.
Close the diagnostic port before clicking Connect. Only one process can own the serial port at a time.
USB mode is G-code transport only. File listings, dashboard graphs, height maps, and firmware object-model browsers require network APIs.
Browser permissions are origin-scoped. A port granted to one local URL may not be visible from another host or port.