QCSer.inf is an INF (Information) file developed by Qualcomm Technologies, Inc. The ".inf" extension denotes that it's an installation file used by Windows to install or update drivers. Specifically, QCSer.inf is related to Qualcomm's USB serial port driver. This file contains instructions and settings necessary for Windows to recognize and interact with Qualcomm-based devices, allowing them to communicate via a serial port over USB.