The modem is an abbreviation for Modulator-demodulator and is a program or a device that helps the computer to transmit data. The information on the computer is stored digitally and the data that is transmitted over the cable or telephone lines are analog. The modem converts a digital signal to analog. It is a device that lies between an electrical cable and the computer based on the internet connection type you have.

How Does the Modem Work?
A modem consists of a connector to the cable present at your house. One end of the cable is connected to the modem and the other end that goes out of the wall is tunneled under the house and is connected to the cable distribution unit. This is then connected to an underground cable which connects to the mounted node of your service provider.
The node captures the feed from the service provider and is sent to your home through the cable distribution unit. The coaxial cable which is the connector of the modem is the endpoint. The resultant speed and bandwidth are determined by the subscription chosen by the user.

Functions of Modems
The modem performs many functions apart from converting signals from digital to analog. They are useful to:
1. Reduce the error in transmission
2. Data compression
3. Information regulation on the network.

Types of Modems:
The modem that you have to choose is based on the interconnection you have opted for. Listed below are some of the commonly used modems.
Cable: These modems are coaxial cable modems where one end of the wire is connected to the modem and the other end to the wall socket or the cable box. It is used for high-speed internet connection.
DSL: It can be either connected to an external modem like the cable having a different plug-in or can be connected to an internal modem which is already present in the computer. A phone line is needed for an internal modem for it to dial-in. The difference between dial-up and DSL is that you can use the phone and still be connected to the internet.
Dial-up: This is a type of modem which is redundant. Like DSL, this modem also uses the phone line to connect to the service provider. These are way slower when compared to cable and DSL and very few people use this. The major drawback of this modem is that if you are on the phone, you will be unable to access the internet.

Difference between Modem and Router
Routers and modems are common computer devices which look alike but perform different functions. A modem is a device that is used to connect to the internet as it connects to the ISP. A router is a device that can help in connecting many computers, laptops or smartphones to the same network. Most routers these days are wireless and they help in connecting devices to the same home network. Connecting to the router does not give you access to the internet, a router must be connected to the modem for it.

Modems are used everywhere today and the most common one is that which we use at home to access the internet.