The USRobotics PCIe Soft Modem Windows Driver is a software driver that allows your computer to communicate with and use a USRobotics PCIe soft modem installed on your system. A soft modem is a type of modem that relies on software to perform many of the tasks traditionally handled by hardware, such as encoding and decoding analog signals. The PCIe designation indicates that the modem connects to your computer via a PCI Express (PCIe) slot, commonly used in desktops for expansion cards.