Difference between Modem and Router

Main Difference

Physically modem and router looks like a same thing but it doesn’t mean that similar thing stands for similar functionality and operation. There are many differences between modem and router. The main difference between modem and router is that modem stands for a device that modulates signals to encode digital information and demodulates signals to decode the transmitted information. On the other hand, router stands for networking device that data packets between computer networks.


modemModem or modulator-demodulator is an internetworking device in which modulator encodes the digital information and demodulator demodulates signals to decode the transmitted digital information. The objective of modem is to generate a signal that can be transmitted speedily and easily and decoded to reproduce the original digital data. Modems can be used with any means of transmitting analog signals, from light emitting diodes (LED) to radio. A common type of modem is one which turns the digital data of computer into modulated electrical signal for transmission over telephone lines and demodulated by another modem at the receiver side to recover the digital data.


routerRouter refers to a networking device that forwards data packets between computer networks. It is connected to two or more data lines from different networks. When a data packet comes in on one of the lines, the router reads the address information in the packet to determine its ultimate destination. Then using information in its routing table, it directs the packet to the next work on its journey. This creates an overlay internetwork. Routers perform the ‘traffic directing’ functions on the internet. A data packet is typically forwarded from one router to another via networks that constitute the internetwork until it reaches its destination node. The most common type of routers are home and small office routers that simply pass data like web pages, email, instant messaging, and videos between the home computers and internet.

Key Differences

  • Layer of modem is data link layer (layer 2), while router layer is network layer (layer 3 devices).
  • Modem contains two ports: one for connection to internet service provider (ISP) and the other is for to connect with router for large networks. Router has 2, 4 or 8 ports.
  • Modem is an inter-networking device while router is a simple networking device.
  • Modem can connect to one computer using Ethernet port while router can connect to multiple computers or networking devices though Ethernet or Wi-Fi.
  • Modem can work without a router while router can transmit information between computers but can’t connect to the internet without a modem.
  • Modem provides no security measures while router provides security measures to protect network.

Video Explanation

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