A cable modem is a device that connects a computer or network to the internet using a cable television line. It converts digital data from the internet into a format that can be transmitted over coaxial cables, which are typically used for cable TV. This allows users to access high-speed internet services provided by cable companies. Cable modems often include built-in routers, enabling multiple devices to connect to the internet wirelessly. They are commonly used in homes and businesses, providing a reliable and fast internet connection. Popular cable internet providers include companies like Comcast and Spectrum.