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, allowing users to access high-speed internet services provided by cable companies like Comcast or Spectrum. Cable modems typically have multiple ports for connecting devices via Ethernet cables or Wi-Fi. They work by communicating with the cable provider's network, enabling users to enjoy fast download and upload speeds, making them ideal for streaming, gaming, and browsing the web.