The DM20S DVB Net Adaptor is a device that allows a computer to receive and decode DVB (Digital Video Broadcasting) signals, typically used for watching digital TV channels over a network connection. The "Net Adaptor" part indicates that this device may connect to your computer over a network (such as Ethernet or Wi-Fi) to access TV signals, rather than using a direct USB or PCI connection.
The Windows driver for the DM20S DVB Net Adaptor is software that enables your Windows operating system to recognize and communicate with the device. Without the driver, the device might not function correctly or might not be detected at all.