DVI cables, or Digital Visual Interface cables, are used to connect video sources like computers to displays such as monitors and projectors. They transmit high-quality video signals, supporting both digital and analog formats, which makes them versatile for various devices. These cables come in different types, including DVI-D for digital signals only, DVI-A for analog signals, and DVI-I that supports both. DVI cables are commonly found in older technology but have largely been replaced by newer standards like HDMI and DisplayPort in modern devices.