A modem is abbreviated into modulator-demodulator. Any internet user quite often gets the doubt between a modem and a router thinking both are similar in nature.
Both are different entities performing two different combinations task to connect and transfer data via the internet. If we put it in plain, a router creates a network between the devices present in your home or office while the modem connects the network created by the router to the Internet.
A router does the traffic forwarding between your computer and internet if connected through a WiFi. You might be wondering why do I get only a single device from the ISP for connecting to the Internet?
Nowadays, the Modem/Router are combined into a single unit which does the functions of the both.
How does Modem work
A Modem is a Network Hardware equipment that modulates carrier wave signals to encode digital information for transmission and perform demodulation to the transmitted analog signals.
The information is transmitted over the telephone or cable lines. Modems can be used by any means of transmitting analog signals from light emitting diodes to radio.
A modem is a bridge between your local network and the Internet. Previously Modem used to modulate and demodulate signals from the telephone lines.
But Modern broadband connections cables, satellites, fibers aren’t working the same way.
In a modem, you plug into any infrastructure you have cable, telephone, fiber, satellites and it gives out an ethernet cable to connect to a single system or a router to connect to the Internet.
Basic Modem Functions
Modulated Signals – It is used to create an easily transmitted and decoded signal that allows digital data to be sent without any information loss.
Data Compression – A necessary step to cut down the time taken for the data to be sent since older technology like the traditional phone lines kind of had limitation on the size and speed so it was essential and mandatory.
Error Correction – Sometimes the information that has been transferred between the modems might be damaged i.e the data might be altered or lost. Information is grouped into frames and each frame has a checksum value. If the Checksum value is a mismatch it might lead to an incorrect data i.e received.
Flow Control – Each and every modem works in different speed and so in order to control the flow of information from as a faster modem to a slower modem. The Character signal is sent to the slower one when it is able to process more data it replies with another character. By this way, the two modems match up their speed
Modem Speed Classification – The Modem speed is based on the amount of data it can send in the specific duration which is expressed in bits per second (bps).
Types of Modem
Based on the Modem Installation they are classified into 3 types
Internal Modem – It is preinstalled in a desktop or computer for communication over the network and doesn’t require any external power supply. Two types of Internal Modems,
- Dial-up modem works with telephone lines and requires a phone number and credentials to log in to the network.
- WiFi Modem connects to the network without filling these credentials.
External Modem – Simplest type of mode doesn’t require to open a computer. Just plug into the wall socket and uses their own power supply so if a connection can be broken quickly. These are DSL Modems which are used for broadband connections.
PC Card Modem – Combination of the Internal and External modem is PC card. Can be used as portable Modems. Plug directly into the slot, the power supply is from PC and only the telephone line is a need for connection. Do not operate PC Card Modem combined with a Machine running on battery which might drastically decrease the battery life.