The Defender USB VCom Port driver is typically associated with devices that use a USB-to-serial or USB-to-RS232 conversion. This driver allows a device (such as a USB modem, certain types of security cameras, or embedded systems) to communicate with a Windows computer via a virtual COM (serial) port.
The VCom Port acts as a virtual serial port, allowing software that communicates via a serial port to interact with the USB-connected device. The term "Defender" could refer to a specific brand of devices that use such drivers, or it could be a part of the device's marketing name, but it's often used in contexts involving USB-to-serial converters.