Conexant HD-Audio SmartAudio 221 is a sound driver package for audio devices, commonly used in laptops and desktops with Conexant audio chips. This driver allows the operating system (in this case, Windows) to communicate with the sound hardware and enable audio playback, recording, and other sound-related functions on your computer.

The "SmartAudio" part of the name refers to software that typically comes with the driver, providing additional features such as equalizer settings, sound enhancements, and possibly advanced settings for microphone input or other audio devices.