Knowing the difference between a modem and a router is important if you want to set up your network or troubleshoot issues with your internet connection. The main difference between the two devices is that a modem lets you connect to the internet, while a router distributes that connection to different devices. A modem is your gateway to the web, while a router is a central hub for your devices.
Many people mistake a router for a modem and vice versa because they can look similar. Both have indicator lights that blink and Ethernet ports on the back. They also share some similar functions. Both transmit data packets or units of data sent from a source to a destination.
But the similarities end there. For one, modem usually has fewer Ethernet ports than a router. A modem also has a public IP address, which can be accessed over the internet. In contrast, a router has a private IP address, which cannot be found on the web. Modems use a wide area network (WAN), while routers span a local area network (LAN), or one with a limited area.
What is a Modem?
A modem relays signals from your Internet Service Provider (such as Comcast, Verizon, AT&T) to your home or office by converting the analog internet signal into digital signals. It is your gateway to the outside world, letting your network connect to the greater internet. Usually, you will get your modem from your ISP when you sign up for your internet plan.
The word modem is a combination of the words “modulation” and “demodulation.” It goes back to the times when modems converted analog signals from telephone lines to turn them into digital signals. Nowadays, more advanced technology is used to do the same thing. But the shorthand term modem stuck, and people continue to use it today.
Modem types include analog, digital subscriber line (DSL), cable, and Integrated Services Digital Network (ISDN). Analog modems use your phone’s telephone line to connect to your ISP. With analog, you can’t use the phone while surfing the web. DSL also uses your telephone line, but the transmission is done outside the frequencies meant for voice calls. This way, you can use both the phone and the internet at the same time. A cable modem functions the same way, only it’s connected to a router or computer through a coaxial cable and a Cat 5 (Ethernet) cord. ISDN is also telephone-based, but it operates from a circuit switch or dedicated line, with signals transmitted over copper telephone wires.
What Does a Modem Do?
A modem is an inter-networking device that modulates and demodulates signals from your ISP to your devices, and vice versa. It modulates (or encodes) information from a transmitter, then demodulates (or decodes) data from the receiver. Think of it as your network’s translator. Basically, it converts proprietary signals from your ISP into a standard signal that your devices can use.
Modems also compress data, correct errors, and control the flow of information. A modem speeds up transmission by grouping data together and submitting them in one go, based on a certain set of rules. Related to data compression is error correction. Here, the modem checks if the information that is sent over matches with certain values assigned to your computer. If it does not match, it sends the data back.
Flow control allows modems to send signals to one another to accommodate varying WiFi and internet speeds. For instance, a slow modem will send a character to a fast modem telling it to stop transferring information until it is ready to do so. Afterward, the slow modem will send another character telling the fast one that it can now proceed with the data transfer.
What is a Router?
A router is a networking device that distributes (or routes) your internet connection from your modem to all of your devices, such as mobile phones, laptops, desktop computers, and smart TVs. This enables them all to connect to the internet at the same time. A router also makes it possible for different devices to communicate with one another over the network.
There are many different types of routers, but two of the popular ones are wired and wireless routers. Wired (or hard-lined) routers need to be physically connected to a modem and a device with cables. In comparison, wireless routers use built-in antennas to communicate with other devices on your WiFi network. However, a wireless router still needs to be physically connected to your modem with a cable to send and receive information from the web.
If you’re in the market for a new router, check out our list of the best routers of 2019 here.
What Does a Router Do?
The main function of a router is to handle the traffic between various networked devices. It keeps track of their MAC (media access control) addresses to ensure information gets sent correctly. For example, if you want to want to watch a video on your phone, your router makes sure it is your phone that receives the video information, not your laptop connected to the same network.
Aside from this, a router makes it possible for users to share resources over the network. These can include files, folders, drives, and computer peripherals like printers, fax machines, and scanners.
A router also has security features that protect you from hackers and other unauthorized people trying to gain access to your network. One of the very basic things you can do to secure your network is to assign a password to it. This can be configured via your router’s settings. From here, you can also enable your firewall, restrict access to devices with a specific MAC address, block certain websites from being accessible, and much more.
If you want to learn more about how to log into your router and change its password, check out our article here.
While a router can do all these things, it cannot connect to the internet by itself. This is where a modem comes in.
Do You Need a Modem and a Router?
If you only need to connect one computer to the internet, you can connect it to a modem with a cable. However, if you want to hook up multiple devices, or you want to have your devices connect to the internet wirelessly, you will need a router. If you have a wireless router, your devices can connect to the internet with WiFi.
If you want to know more about what WiFi is, and how it works, check out our previous blog here.
Router-Modem Combo Devices
Nowadays, some ISPs provide subscribers with a router-modem combo. This two-in-one device doesn’t require as many wires or cables to set up. However, if you want more flexibility, you might want to consider buying a separate modem and router.
Buying a third-party router will give you more control over features like network and USB connectivity, parental controls, and file and printer sharing. Routers can be used with a broadband connection from any ISP. This means that when you switch to a different provider, you can still use the router you already have.
Having a standalone modem and router will also make future upgrades easier. You might want a router with the latest WiFi technology, or with better coverage, or one which can connect more devices. In that case, you can buy a new router without having to buy a new modem as well. Upgrading piecemeal makes sense, especially considering that router technology evolves much faster than modem technology.
Purchasing your own modem will also help you slash your internet bill. ISPs charge $8 to $10 a month for rental modems, which can add up over a year. If you plan to stay with your provider for a few years, you can recoup rental costs by owning your own modem. Just make sure to check with your ISP to see if your modem is compatible with your kind of internet service.