Modem Vs Router: Know The Exact Difference

Know What is the exact difference between a Modem and a Router:

In our last tutorial, we explored all about Network Vulnerability Assessment in detail.

In our other tutorials, we have already discussed in detail about the working, configuration, and set-up of routers with the help of different examples in the networking system. However, we have not understood the importance and role of Modems in the communication system.

Here, we will cover the working of modems and then we will compare the various aspects of working principles with a couple of examples of modems with routers.

Suggested Read => Absolute Networking Guide for Beginners and Experienced

modem vs router

What are the Modem and Router?

It works on the data-link layer of the ISO-OSI reference model and provisions the transmission of data packets. The modem performs the modulation and demodulation function in between your networking devices such as a computer or router and the telephone line.

Further reading => Top Wi-Fi Routers available in India

The main purpose of using a modem is that it connects the networking system or device to the Internet service provider (ISP) and we can get access to the Internet only by using a modem.

The connection between the modem and the networking device is done by using RJ45 cable and between the modem and telephone line is by using RJ11 cable.

Block Diagram of the Modem

building block of modem

[image source]

Modem and Router in the Network

modem and router in the network

Modem and Router – Connection to the Internet

modem and router to Internet

[image source]

Recommended Reading =>> Analog Vs Digital

Modem and Router Comparison in Tabular Format

Basis for comparisonModemRouter
DefinitionA Modem is a device which performs both modulation and demodulation of signals.The router is a networking device which associates various networks with each other for LAN and WAN networks.
Layer It works on the data-link layer of the ISO-OSI reference model and doesn’t have any inbuilt intelligence.It works on the physical, data-link and network layer of the ISO-OSI reference model and maintains the routing table to forward and route the data packet to the desired destination path.
Working PrincipleIt acts as a modulator and demodulator. It modulates the digital signal of the computer or router to the analog signal of the telephone line so that easily understood by the telephone line when getting through it and performs the demodulation function at the other end by converting the analog signal which comes from the telephone line into a digital signal for the network device like PC.It doesn’t perform any type of modulation and demodulation function, but it routes a data packet between source and destination end by following the shortest path and securely directs the data packet by following the routing table. The router permits various network devices to connect into the network.
PurposeThe modem plays a very vital role in the communication system as it is an essential part of the networking system for connecting any device to the ISP. The modem brings out the requested data from the ISP to the end device like a PC or router. If we need to connect only one computer to the Internet then the modem can do it, it doesn’t require the router.It routes the data packets among the networking devices and the different networking systems. The router is one of the basic building blocks of the WAN communication system.
Security It delivers the information as it is in the form it derives it from the ISP without checking any security threats as it is not smart enough to get it examined. Thus any threat can easily get access to the network through a modem.The router uses a firewall to examine the incoming data packets and filters the unwanted data packets by using the firewall and other antivirus software. Thus it is difficult for the unwanted material to enter the network by means of the router.
PlacementIt is placed between the telephone line and the PC or router.It provisions connectivity with both wireless or wired like optical fiber, telephone line medium. The connectivity is done by the Ethernet port available with the modem. It connects the ISP to the single PC for the home or office network connections.It is placed between a modem and the network system. The network can be a set of computers or a set of computers and switches etc. The modem and router are physically connected with each other. Therefore the devices which are associated with a router can access the Internet via a modem. It doesn’t provide the direct connectivity with the ISP as it doesn’t work at the physical layer. It works at the network layer. The router has the Ethernet and gigabit ports to connect with the different network devices and other networking systems. The routers also have the Wi-Fi port for wireless connectivity.
Physical Connectivity Modes1. Half Duplex Mode.
2. Full duplex modem-
3. Four wire modem-
4. Two wire modem
The details has been explained in the end of table.
The modes are entirely different from the modem as the router works on the network layer. The different modes are-
1. User execution mode
2. Administrative mode-.
3. Global configuration mode
Applications1. The basic application of the modem is to connect the end users with the Internet. But it is widely used these days for other purposes also.
2. Point of sale (PoS)
3. Remote management
4. Data transfer and backup
The details are discussed after the end of table.
1. The use of the modem is limited to only LAN connectivity but the routers are used for LAN as well as WAN communication networking. In fact, the routers are a basic building block of the mobile communication system.
2. Provision redundancy in the network.
3. Data storage and backup of huge capacity.
4. Confidential services.
5. The modem is also used for data transfer and backup process but only for short distance and the process is slow. While by configuring VPN in routers it can work in client-server architecture, and be used for sharing data, voice, hardware resources and video for WAN networks also.
Merits1. Allows the end devices like a PC or laptop to access the outside world through the Internet.
2. Can easily be installed and dial-up modems use a telephone line for making internet connections which is easily available everywhere even in remote areas.
3. Less maintenance cost.
4. The USB modem is very cheap and compact and easy to carry everywhere. It is compatible with the laptops and doesn’t need charging thus can be used anytime for accessing the Internet and for long duration also.
1. Allow multiple devices to connect with the routers to construct a network and connected via the internet through the modem.
2. Offer high-speed data transmission than that of modems by using high bandwidth STM link for connectivity over fiber optics thereby best suitable for both wired and wireless communication.
3. Unlike Modems, routers have the firewall and other in-built security features installed within it to deal with the various virus attacks and network threats. Thus routers are less vulnerable to security threats.
4. Have the feature of access restriction thus can use to store sensitive data as not everyone can easily access the data stored in it. They are secured with network username and password credentials.
5.        Routers continuously work in master and slave mode thus provides the redundancy to the network. Thus shield the network from complete failure.
Demerits1. Easily vulnerable to network threats as there is no way out in modems to scan for security threats.
2. The dial-up modems working speed is very slow and power consumption is very high.
3. They are not used for WAN communication purpose.
4. Anyone from the outside world can enter the network and harm network devices as most of the modems don’t have the feature of access restriction.
1. Very expensive in cost and hardware routers like ZX T1200, Cisco 2000 series routers are difficult to install.
2. They work only based on some set of routing protocols and analyze various algorithms to find the path to the destination. Thus induce congestion in the network.
3. The overall architecture of the router network is complex as we need to assign a unique IP address and subnet mask to each of the network element for communication which is very difficult to memorize.
Types1. Dial-up Modem
2. DSL Modem (broadband modem)
3. Cable modem
4. Mobile broadband Modem
Details are discussed at the end of table.
The classification of the router is based on software and hardware type. These can be used both with a wired or wireless connection.
1. Hardware Routers
2. Software Routers
Details are discussed at the end of table.

For a detailed analysis of the above comparison please refer to the following details given below:

Modes in Modem

#1) Half Duplex Modem: It allows the modem to transmit in one direction at one time. If the modem is receiving the incoming signal then it gives indication light to the sending end to not to transmit data unless the receiving of the signal is completed.

#2) Full Duplex Modem: It permits transmission in both the directions at the same interval of time. These kinds of modems have two carriers on the line i.e. one is for outgoing traffic and the other for incoming traffic.

#3) Four Wire Modem: A separate pair of wires is used for the incoming and outgoing carrier. Thus same frequency can be used for transmission at both the ends.

#4) Two Wire Modem: It utilizes the same pair of wires for both incoming and outgoing carriers. If we are using the half-duplex mode then the same frequency can be used for transmission as data flows in one direction only at a time.

However, if we use the two-wire modem in full duplex modem then we need two different channels for transmission. Thus frequency division multiplexing is done to obtain two carrier channels so that the transmission would take place simultaneously in both the directions.

Modes in Router

#1) User execution mode: This mode is also known as the default mode. It is represented as ‘Router>’. When we purchase the router and firstly login into it, we have some basic settings and configuration already done in the router and the web interface will show this mode.

#2) Administrative mode: This mode is represented by ‘Router#’. In this mode, the administrative rights are given to the user and the username and password to access the router are set and reset. The other login rights are also granted and denied through this mode.

#3) Global configuration mode: This mode is represented by ‘ Router (config)#’. In this mode all the configuration is done on the router like allocating IP addresses, subnet mask, routing data packet, enabling ports and allocating routing protocol to be used for routing, etc.

There are some of the sub-modes as well like interface configuration mode and line configuration mode that is used to perform the configuration on a particular port or interface of the router.

Applications of Modem

#1) Point of sale (PoS): It is the backbone of the payments that you made at the restaurants, retail stores, air-tickets payments, etc. When you do any payment with your credit or debit card the modem is there in the backend (dial-up or broadband) for transferring data and reverting back the approval or denial of the services requested.

#2) Remote management: The modems are mounted in the remote area locations like interior or sensitive areas and the performance can be managed and controlled remotely by using modems without been physically present at the site.

This, in turn, saves money and time and is usable in critical failure time when quick action is required to restore services. It is used in red-light controls, gas station maintenance, industrial inventory management, etc.

#3) Data transfer and backup: The dial-up modems are used to transfer the data on a daily basis from various locations of the organization to the NOC center. They are time-effective and cheaper to use for this purpose. It is also used in taking regular backup of data from the devices.

#4) Home security management: The modems are installed in the security management systems. When some issue arises or alarm is set-off then they send a voice message to the client over the telephone line or via mobile.

Applications of Router

#1) Data storage and backup: Routers have in-built storage capacity with sufficient memory to store data. Thus external hardware device is used in association with the routers for data sharing and backup.

#2) Confidential Services: As the routers are having security features, we can plant a firewall with routers at every level of the network to make the network virus free. Thus it is used for military purposes where data privacy is a major concern.

#3) The modem is also used for data transfer and backup process, but only for a short distance and the process is slow. While by configuring VPN in routers, it can work in a client-server architecture, and be used for sharing data, voice, hardware resources and video for WAN networks as well.

#4) Provision redundancy: Operation and maintenance center for an organization use to connect various far end location devices to a centrally located NOC center through routers. Routers also provision the devices to work in main and protection link topology to provide redundancy in the network.

Types of Modem

#1) Dial-up Modem: The modems which are using the analog telephone line to connect two end devices such as two PC’s is known as a dial-up modem.

It provisions interface between the digital system and analog system as it modulates the binary data into the carrier signal on the telephone line and demodulates the carrier signal into the original data bits at the receiving end of the PC. The speed of dial-up modems is limited to 56kbps.

#2) DSL Modem (broadband modem): These make use of twisted pair cable for transmission of signals, therefore, will radiate on much higher frequencies and can cover a bit longer distance than the dial-up modems. These provision faster speed for transmission which is 2 Mbps and even more depending upon the type and configuration.

#3) Cable modem: They are designed in a way to carry radio and television signals apart from being used for the internet. It works almost similar to DSL modems.

It can be configured internally or externally with the television line to be used for converting the signals into the compatible mode. However, the cable modem is not deployed with a DSL connection and vice-versa.

#4) Mobile broadband Modem: Modems which make use of mobile telephone line such as UMTS, GPRS or Wi-Max are known as mobile broadband modems or wireless modems.

They are used with the laptop or PC’s as a USB modem by inserting them into the USB port of the device to access the Internet. These are also known as dongles and have an inbuilt slot for inserting the SIM card. They offer high and good quality internet speed and performance.

Types of Routers

#1) Hardware Router: The hardware routers have an inherent software capability which is designed by the manufactures. They have default configuration in-built settings when you purchase them. They follow their own default routing table to obtain the route for packet delivery.

These also have other enhanced features like an innate firewall to scan the security threats etc. which is not present in the modems. Also unlike modems, the transmission speed of routers is very fast and is not limited. They have multiple Ethernet and gigabit ports for connection with other devices for networking.

#2) Software Routers: These don’t have any hardware unit. These work similar to the hardware routers but are more often used as gateways or firewalls as they are like servers with an in-built web interface like windows or Linux. It is basically used for WAN routing purpose and they have limited ports.


From this article, we have explored and understood the basic working principle and purpose of using modems and routers in the computer networking system.

Recommended reading =>> What is Digital Signal Processing

We have also analyzed the point-to-point difference between the two devices on the basis of the application, modes of operation, types, merits, and demerits.

Hope this tutorial would have been helpful to you in knowing the exact differences between Router and Modem!

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