What is a modem and what does it do?

Internet Basics
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A modem is a networking device that connects your home or business network to your internet service provider (ISP).

Its primary job is to establish communication between your local network and your provider’s network. Depending on the type of internet service you have, the modem may communicate using cable, fiber, DSL, fixed wireless, or other technologies.

In many homes, the modem works together with a router. The modem provides internet connectivity, while the router distributes that connection to devices such as computers, smartphones, gaming consoles, smart TVs, and other connected devices.

Some internet providers supply a combination modem/router device that performs both functions in a single piece of equipment.

Understanding the role of a modem can make it easier to troubleshoot internet connectivity problems and understand how your home network is connected to the internet.

Key Takeaways

  • A modem connects your network to your ISP.
  • The modem provides access to the internet.
  • Routers and modems perform different functions.
  • Some devices combine modem and router functionality.
  • Modems are commonly used with cable, fiber, DSL, and other internet services.

Related Resources

Related Community Discussions

Discussion Questions

  • Does your home network use separate modem and router devices?
  • Have you ever replaced a modem to solve a connectivity issue?
  • What questions do you have about how modems work?
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One reason modems and routers are often confused is that many internet providers supply equipment that combines both functions into a single device.

As a result, users may refer to the device as a modem, a router, or even a Wi-Fi box, even though it may actually be performing multiple networking functions.

Understanding the difference can make troubleshooting much easier when internet or Wi-Fi issues occur.

What do you call the networking equipment in your home?

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I’ve found that networking conversations often become much simpler once everyone agrees on which device they’re talking about.

Many support calls start with someone saying their modem isn’t working, only to discover they’re actually referring to the router—or vice versa. Understanding the role each device plays helps eliminate a lot of confusion when troubleshooting connectivity problems.