Windows XP/Vista/Vista64 Serial USB Driver for PIC18F

When plugging a new USB device, Windows checks all its INF files to load the appropriate driver. The INF file contains the Vendor ID, the Product ID or the USB Class definition. If the VID/PID or the USB Class Definition of the USB device matches with one INF file, Windows will load the driver described in this file. There is no driver required for Microsoft Windows as the adapter using the standard Communication Device Class (CDC) driver usbser.sys included in the distribution. Windows doesn’t have a standard INF file for the CDC driver and Microchip provides one as part of USB Framework package. Alternatively you can download the driver from here.