Hello friends! Today in this article we will read about Modem. It is written in very simple language. Read it completely, you will understand it easily. So let’s start:-
What is Modem?
Modem is a hardware device which is used to communicate from one system to another. This device uses telephone lines to communicate between systems.
In other words, modem is an input and output device which is used to transfer data from one device to another over the telephone line.
This device converts digital signal to analog signal and analog signal to digital signal. This device is used to establish internet connection.
Modem is used to establish internet connection because internet sends analog signal to the computer but the computer can only understand digital signal, therefore using modem the analog signal is converted into digital signal so that internet connection can be established.
Types of Modem
It has the following types which are explained below:-
1- External Modem
It is a type of modem that is connected to the external part of the computer system using a cable.
External modem is very easy to install and can transfer data at very high speed.
To operate this modem, COM and USB port is required and this modem is also quite expensive.
2- Internal Modem
This modem is also known as on-board modem. Internal modem is installed on the motherboard of the system.
Compared to external modem, it is quite difficult to install internal modem and the speed of transferring data in this modem is also very slow.
This type of modem is mostly used in homes or small places.
3- Wireless Modem
This modem connects with the system without a cable. In simple words, no type of cable is required to connect the wireless modem with the system.
This modem is mostly used by people for personal use. This modem uses radio signal to transfer data and its speed of transferring data is also fast.
4- Cable Modem
Cable modem is also known as broadband device. Cable wire is used to connect this modem with the system.
This modem is used by ISP (Internet Service Provider).
It helps the system to communicate with the ISP (Internet Service Provider) over a landline connection.
5- DSL Modem
The full form of DSL is (digital subscriber line) in which data is transferred over the telephone line.
This modem can transfer data at a fast speed so this type of modem is mostly used in offices and homes.
There are two types of these: ADSL modem and SDSL modem.
6- Satellite Modem
This modem does not require the use of any type of telephone connection to get internet connectivity. This modem is quite expensive.
It uses satellite technology to transfer data. Satellite modem can transfer data at a faster speed compared to DSL and Cable modem.
7- Half-duplex Modem
In this modem, data can be transferred in only one direction at a time.
Functions of Modem
1- Modem compresses the large size of data due to which it takes less time to transfer the data.
It uses compression technique to compress the data.
2- It monitors the data, with the help of which it is easy to detect errors in the data. To do this, the modem divides the data into small units, a process called frames.
After this, the data present in the system is scanned using checksum technology. If any kind of error is detected in the data, then that error is corrected and after this the data is transferred to another device.
3- The main function of the modem is to convert the signal. It converts digital signal into analog signal and analog signal into digital signal.
4- This device controls the flow of data. It transfers data at different speeds. Some modems transfer data at a fast speed while some modems transfer data at a slow speed.
In such a situation the data may get damaged, hence the modem controls the flow of data so that the data is not damaged.
Advantages of Modem
1- This device transfers data at high speed.
2- It helps to connect LAN (Local Area Network) to the Internet.
3- This device is easy to install.
4- Cable modems are able to download files at faster speeds.
5- Using this device the system is connected to the internet.
6- This device sends and receives fax messages at high speed.
7- This device is easily available in the market.
Disadvantages of Modem
1- By using modem, malware like viruses can enter the system and data and files can also be damaged by hackers.
2- It is difficult to maintain traffic in these devices.
3- Its Dial UP Connection is very slow due to which the user’s call gets disconnected while making a call on the telephone line.
4- If fibre optic cable is not used with this device then the user may face problems like slow internet speed.
5- These are very expensive devices.
Difference between Modem and Router
| Modem | Router |
| A modem is a device that modulates and demodulates electric signals. | It is a networking device that connects devices with wired and wireless networks. |
| It operates at the data link layer of the OSI model. | It operates at the physical, data-link, and network layers of the OSI model. |
| This device transfers data without any authentication so it is not secure. | It uses login ID and password so it is a secure device. |
| It is used to connect to an RJ45 router and to connect to RJ11 telephone lines. | It is used to connect to RJ45 telephone line. |
| The modem is placed between the telephone line and the computer. | The router is placed between the modem and the networking device. |
| The modem can be connected to only one device. | The router can be connected to multiple devices using ethernet cable and Wi-Fi. |
| It uses two ports to connect the system to the ISP. | It uses two to four ports to provide Internet connection to the system. |
How does a modem work?
A modem has two types of plugs, the first plug connects the system with the cable wire and the second plug connects the system with the WiFi router.
The main function of the modem is to convert signals so that data can be transferred. It converts digital signal to analog signal and analog signal to digital signal.
After this, this device transfers the data from one device to another with the help of telephone lines. The process of converting the signal is also called modulate and demodulate.
Questions asked in the exam
What is a modem?
Modem is a hardware device which is used to communicate from one system to another.
What is the main function of modem?
The main function of a modem is to convert signals so that data can be transferred.
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