A modem is a device that connects your computer or network to the internet. It converts digital data from your device into analog signals that can travel over telephone lines or cable systems. This process allows you to access online content, send emails, and browse websites. There are different types of modems, including DSL modems and cable modems, each designed for specific types of internet connections. Some modems also include built-in routers, which allow multiple devices to connect to the internet wirelessly. Overall, modems play a crucial role in enabling internet connectivity for homes and businesses.