Although Modem and Router look like similar devices, they serve different functions. A Modem is not the same as a Router and understanding the difference between a Modem and a Router is important, both for academic and practical purposes.
What is a Modem
A Modem can be defined as the first point of contact for internet traffic flowing in to your Home or Office network. The Modem connects to the network of your Internet Service Provider using a coaxial cable or a telephone cable, depending on whether you have a Cable or a DSL powered internet service.
Going by the nature of connection, Modems can be classified as Cable Modems and DSL Modems. Cable Modems make use of a Coaxial Cable Connection (similar to Cable TV) to connect to the Cable Port on the Wall of your home, which in-turn is connected to the cable network of your Internet Service Provider.
A typical DSL Modems is connected to the telephone socket on the Wall of your home using a telephone cable and a connector known as RJ-11 jack. The Wall Socket is connected to the telephone network of your service provider.
What is a Router
A Router can be defined as a device that allows various devices to share a network connection. Initial routers only had multiple Ethernet ports that allowed devices to connect to a local area network (LAN).
In comparison, Modern Routers are mostly used for creating a WiFi network, so that multiple devices like laptops, tablets, printers and phones can connect wirelessly to an internet connection.
A Modem by itself cannot provide you with an internet connection. The Router needs to be connected to it in order to create your home WiFi network that multiple devices in your home can connect to.
Hence, most Routers have a specific Ethernet port, designed to connect to the Ethernet port of a Modem. Modern routers also have other multiple Ethernet ports that you can be used to provide wired internet connection.
Typical Home Network Setup
Here is what a typical home network looks like
1. Internet Service Provider (ISP) brings connection to the wall mounted Cable port/Socket
2. Modem gets internet connection from the wall mounted Cable Port/Socket
3. Router gets internet connection from the Modem and creates a Home or Local WiFi Network
4. Desktop, Laptops, Tablets, Printers, Phones etc connect to the Router For Internet
Combined Routers and Modems
While Routers and Modem serve different functions, some internet service providers like to offer their users with combo devices that function both as Modem and Router.
However, you can still use your own Router by plugging the Router to one of the Ethernet ports of the combo device. This offers you with more control (parental Control Settings) and better performance, in case your Router is more advanced compared to the ISP provided Modem/Router combo.
Difference Between Modem and Router
A Modem can only connect to one device, it can either be connected to a PC or a Router. While a Router can connect to multiple devices, either through a wired connection using Ethernet cables or through a WiFi network.
A modem passes the data as it receives from the internet without screening the data. A Router in most cases is equipped with firewalls to screen the data and examine data packets.
A Modem has 2 ports, one port connects to the Internet Service Provider and the other one connects either to a computer or a Modem. This means that a Modem can work without a Router, providing internet connection to a Single PC.
In comparison, Routers cannot connect to the internet without being connected to a Modem. Routers come with 2, 4 and 8 ports for enabling wired connection to multiple devices in addition to the wireless WiFi connection.