The firmware is the program code running inside the ARS-USB microprocesor. This firmware can be loaded, thanks the microprocessor includes a utility called bootloader and allows reprogrammed.
This is the driver for Windows XP, Vista, 7 – 32/64 bits. This file is usefull for Windows to detect the device and recognize it as a CDC device attaching it to a serial port. The driver works on both S.O. 32 and 64 bits.