Troubleshooting

1.Could not connect to device.

A. Make sure that the COM port number (for Windows) or TTY (for Linux and Mac OSX) appear when the device is connected.
If the serial port is not recognized, then uninstall and then reinstall the driver. In some cases, you may need to reboot the PC after driver installation. The j4210 driver is not in path.

2. Could not detect type of card.

A. If card type is not detected, then the card may be password protected. In this case, the user may pro programmatically set the card type.

3. Could not perform inventory.

A. Possibly there were no tag on the device. If there are tags, make sure that they are UHF RFID tags. If still could not detect tag, then move the tags to the center of the reader then try again.

4. Not all tags are detected in the first scan.

A. Read through Optimal Setup for detailed discussion on this topic.

5. Attaching device does not cause any serial port to appear.

A. This happens in older OSes. New OSes have automatic detection of USB to Serial generic driver and have no problem in communicating with the device.
If your OS does not show a serial port when device is connected to USB port, first install a driver from here: https://www.microchip.com/en-us/product/MCP2221.
If the driver does not resolve the problem, remove the device and go to /dev folder (for linux) and count the number of devices there.
Then attach the device and count the number of devices in the /dev folder again. If there is a change, then find the name of the newly added device and send it to us. We will add the new device into our driver within a short time and release the new driver.