Modem vs Router: What’s the Difference?

The Internet has become an indispensable thing in our life. Modems, routers, hubs and network switches are widely used in building a network. When it comes to setting up a Wi-Fi network, it’s necessary to know what kind of network equipment you need. A modem and a router are the foundation of your Wi-Fi network. A modem can connect you to the Internet, while a router can connect your devices to Wi-Fi. As the carrier of the network, what's the difference among Optical Network Unit vs router? How can we distinguish them? In this article, we will answer these questions.

What is Optical Network Unit (ONU)?

ONU (Optical Network Unit) is also called optical modem, which is a device similar to the baseband modem. But the difference is ONU accesses optical fiber. It converts the digital signal into analog signal through modulation at the transmitting end and transmits the analog signal into digital signal.

Modem is a Bridge Connecting Your Local Network and the Internet. Short for modulator-demodulator, a modem serves as a bridge between your local network and the Internet. It encodes and decodes data. So the data can be transmitted between the home network and the Internet Service Provider (ISP). A modem connects to a router or directly to a computer, by using an Ethernet cable. Thus you can get an Internet connection. Besides, most modems have two ports: one connects to the Internet and another connects to a router or a computer.

What is Router?

Router is a gateway that connects two or multiple networks, which can read the address in each packet and decide how to transmit it. A router directs the Internet connection to all your computers, mobile phones and other connected devices you have. It connects to a modem through an Ethernet cable. And then the router passes that Internet connection to other devices in your house through an Ethernet cable or over a Wi-Fi network. It creates a private wireless network in a home, office, or place of business. For example, when you connect your cell phone to Wi-Fi, the cell phone is connected to a local router. A router lets all your devices communicate with one another over the local network. Besides, a router can protect your devices from being exposed directly to the Internet. To the Internet, all the traffic coming from your private network looks like it’s coming from a single device. Thus, the router can connect non-TCP/IP networks to the Internet.

Optical Network Unit vs Router

Although ONU, router and switch are used for the Internet, there are different applications. Generally, the analog signal transmitted by the network cable is converted into a digital signal through the ONU. Then, the router forwards the signal to the PC. When the number of PC exceeds the number of routers that can connect, a switch needs to be added to expand the interface. When it comes to connecting your home devices to the Internet, we can’t miss modems and routers. A modem brings the information in, and a router distributes it to different devices like computers and phones. The following chart will show you the differences between modem vs router in detail.


A modem can connect you to the Internet, while a router can connect your devices to Wi-Fi. Modems and routers are both involved in connecting your home devices to the Internet. The differences between modem vs router include many aspects, such as layer, function, the number of ports, data transmission form, device type, etc. Except for modems and routers, switches such as Gigabit Ethernet switch and 10GbE switch also play an important role in building a network.

LightOptics is a professional manufacturer supplies all kinds of fiber optic tools, including network cable tester, cable stripper, punch down tool, telephone line tester, fiber cable stripper, cable crimping tool, etc.

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