The serves as a translator. It tells your operating system, "I know this is a USB cable, but I want you to treat it like a legacy Serial Port." This allows legacy software (like older logging programs or rig control software) to communicate with the radio using standard COM port logic, while modern software can access the audio channels via the same cable.
The is actually a standard Silicon Labs CP210x driver, but its correct installation is the gatekeeper to the radio’s digital soul. Whether you’re chasing DX on 23cm EME, running the 144MHz contest with N1MM, or casually working FT8 on 2m, a stable USB link is non-negotiable. icom ic-9700 usb driver