: If using a generic third-party cable, confirm it is capable of data transfer; many standard USB cables are wired for charging only and will not appear in Device Manager.
If you have an older OPC-1122U (Prolific chip) and Prolific’s new driver rejects it as a clone, you must disable driver signature enforcement temporarily: icom opc-1122u driver
Remove the OPC-1122U from your computer. Do not have it plugged in during initial installation. : If using a generic third-party cable, confirm
If the device shows as “Unknown Device” or “USB Serial Converter” with a yellow exclamation, the driver was not installed correctly. the driver was not installed correctly.