What is a modem?

A modem connects your network to the Internet, while a router allows your devices to use that connection or communicate over a local network.


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The Internet is so critical to our daily lives; it’s no wonder that the United Nations declared Internet access a human right in 2016. Without an Internet connection, we can’t quickly consume news, send emails, check social media pages, stream entertainment content, or find recipes instantly. It’s funny to think that helping us connect to the web and potentially billions of gigabytes of data is a small little device called a modem.   

What is the purpose of a modem?

A modem connects you to the Internet. Think of a modem as a translator that allows devices like computers, switches, or routers to connect to the Internet by interpreting signals from an Internet Service Provider (ISP). Typically, these signals are sent across coaxial cables or phone lines.

What does a modem look like?

Modern external modems are often black or white rectangular vertically standing boxes. These devices also have blinking lights on one side and an array of ports on the other. Internal modems, meanwhile, look like flat plastic cards with metal circuitry.

What does modem mean?

The word “modem” is a portmanteau of “modulator-demodulator.” It’s called a modulator-demodulator because it modulates digital signals to analog signals and demodulates analog signals back to digital signals. By modulating digital signals to analog, a modem allows a computer to transmit data as electrical pulses over wires to other computers. Likewise, a modem converts the pulses to the original digital information that receiving computers can read when demodulating.

Types of modems

Internal modems

A modem card is an internal component that fits on a motherboard’s expansion slot, like Peripheral Component Interconnect (PCI). Internal modems typically use telephone landlines for dial-up Internet access. These types of modems are less popular nowadays than the external variety.

External modems

An external modem is a self-contained device that sits outside a computer and draws power independently. External modems usually feature lights that show the status of a connection. Such modems can use cable or DSL for broadband Internet or phone lines for dial-up Internet.

Why did dial-up modems make noise?

Some dial-up modems make the type of loud electronic hissing and screeching noise that you’d expect from angry droids in Star Wars. So, why did dial-up sound like that? To keep it brief, the hissing is the sound of modems putting out feelers to agree on the communication protocols and establish a valid connection in a process called handshaking.

What is the difference between a router and a modem?

In simple terms, a modem connects your network to the Internet, while a router allows your devices to use that connection or communicate over a local network.

You’d be forgiven for thinking that a router and a modem are the same things because modem-router combos are highly convenient and popular all-in-one devices. However, routers and modems are different devices. While a modem converts analog signals sent by an Internet Service Provider (ISP) over wires to digital data for a computer or router to understand, a router forwards data packets to other devices on a wireless network or through an ethernet cable.

Is a modem the same as WiFi?

Although both can have something to do with the Internet, a modem and WiFi aren’t the same things. A modem is merely a device that manages digital and analog information transmitted across wires to help computers access the Internet. So, then what is WiFi and how does it work with a modem? Well, a wireless router uses wireless technology called WiFi to create a network to transfer files or stream content. A router can also use WiFi to share the Internet from a modem in a network.

A modem isn’t enough to establish or connect to a WiFi network. Likewise, modems are incapable of sending this radio signal to other devices on their own. For Internet ready WiFi, you’ll need a wireless router in addition to a modem.

Can I get Internet with just a modem?

Yes, you can get an Internet connection with just a modem that’s the right match for your ISP. For example, if your ISP provides broadband Internet over cable, you’ll need a cable modem instead of a dial-up modem. You can typically connect your computer to a modem through an ethernet cable. But to share that Internet connection wirelessly with other devices, you’ll need a wireless router. Alternatively, can buy a 2 in 1 box that carries a modem and a router. 

On the other hand, can you get Internet without a modem? Not usually. Even when you use WiFi to connect to the Internet from a mobile device at the mall, that connection is probably online because of a modem.

Can a modem be hacked?

Both routers and modems can be hacked. For example, Danish researchers found a security flaw in hundreds of millions of cable modems worldwide named Cable Haunt. Attackers with local network access can exploit the flaw to redirect users to malicious websites or launch man-in-the middle attacks. Similarly, home routers can be hijacked by hackers with the right skillset and tools. We recommend you update your Internet devices with the latest security patches whenever they become available.