Device not detected

No port appears

1. Replace the cable with a known USB data cable.
2. Connect directly to another USB port.
3. Disconnect the BLE extension temporarily if the power state is unclear.
4. Check Device Manager on Windows or /dev serial nodes on macOS/Linux.
5. Install or update the CH343 driver.
6. Test on another computer to separate host and hardware problems.

The port exists but connection fails

1. Close every program that might have opened the port.
2. Set the device host interface to USB.
3. Start with 115200 baud.
4. Reconnect the device and reselect the port; its name may change.
5. In the PN532 CLI, run debug on, reconnect, and inspect whether any ACK is received.
6. Return to Reader/PN532 mode before connecting generic PN532 software.

Intermittent disconnects

• Avoid loose adapters and unpowered hubs.
• Do not move the extension cable while powered.
• Lower the configured UART rate.
• Keep high-current or noisy RF equipment away from the USB cable.
• Confirm that the host is not suspending the USB port.