Troubleshooting

Start with the symptom you can observe. Apply one change at a time, then retry the Quick Start.

Symptom	Check	Fix
No data in either direction	The TX and RX wires.	Connect TXD of the adapter to the RX pin of your board, and RXD to TX.
The board you connect gets no power	The position of the VCC voltage select switch.	Move the switch to the voltage your board needs. It sets only the VCC pin.
Your board uses 5 V logic	The TX and RX lines are always 3.3 V logic, whatever the switch says.	Check your board's logic level before you connect it.
The PWR LED stays off	Whether JP2 was cut.	Close JP2 again, or ignore the LED. It only shows power.
No new COM port on the computer	The USB-C cable and the driver. The CP2102N needs the Silicon Labs Virtual COM Port (VCP) driver.	Try another cable, which must carry data, not only power. Get the latest driver from `silabs.com/interface-software`.

Still blocked?

Ask on the community forum. Include the following so someone can reproduce it: