What is Modem | Types of Modem and Uses of Modem

Modem stands for modulation and demodulation. The modem is a device that converts the digital signal into a form that can travel over telephone lines or radio (Analog Form) and from analog to digital.

The process of converting the digital signal into an analog signal is called modulation and the process of converting the analog signal into a  digital signal is called demodulation.

Digital modulation refers to the process of encoding a digital signal onto a transmission medium, such as a wired or wireless channel, in a way that enables the signal to be accurately received and decoded at the receiving end without any loss of information.^[1]

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The modem sends data from one computer to another through telephone lines. Computer stores data in digital form. Since a modem transmits data using a telephone line, so it is converted from digital to analog form. The sender and receiving device must have a modem.

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Features of Modem

Key Points

• A modem converts digital signals to analog signals for transmission over telephone lines or radio and vice versa.
• Modem speeds range from 300 bpt to 56kb bpt.
• Modem tests digital and analog connections provides voice conversation while data is transmitted, and uses error control methods.
• Modem types include external, internal, and wireless.
• Modems are used in point-of-sale systems, online shopping, data transfer, home security monitoring, and gasoline vapor containment systems.

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There are some important features of modems are

Speed

Speed is the rate at which the modem can send data in bpt. Typically modem speeds are 300 bpt to 56kb btp.

Self-Testing

The modem can test the digital connection with the computer. It can also test analog connections with a remote modem.

Voice over data

 The Modem provides the facility of voice conversation while data is being transmitted. Both the source and destination modem should have this feature.

Error Control

Modem uses different methods to control errors for transmitted data.

Types of Modem

There are different types of modems in terms of physical size and shape as follows

External Modem

The external modem is attached to the system unit like an external device through a telephone line. It is connected to the telephone wall jack by another cable.

An external modem is connected to a computer using a serial cable COM1 or COM2 port. It requires an external power supply. It is easy to set up. An external modem is expensive.

Internal Modem

An internal modem is a circuit board that is inserted into an expansion slot on the motherboard. It cannot easily be moved from one computer to another. It is more difficult to set up than other types of modems. It is less expensive than an external modem.

Wireless Modem

A wireless modem transmits the data signals through the air instead of a cable. It is also known as a radio-frequency modem. It is designed to work with cellular technology and wireless local area networks.

Uses of Modem

The modem is playing role in different areas.

Point of Sale (POS)

Now a day. Every consumer tries to pay through a debit card, credit card, or net banking where the modem plays an important role in the behind with of transferring data as well as returning an approval.

For example: Use for ticket machines in the airport, bus stations, and railway stations Online Shopping with net-banking

•  Use ticket machines in airports, bus stations, and railway stations
• Pay bills via credit or debit card in PVR, hotels, or shopping malls

Data Transfer

• Big organizations use modems to send data to send their franchise.

Some more uses of Modem

• The modem is used in home security monitoring.
• It is also used for Cinema screening approval
• Cell phone tower maintenance
• Gasoline vapor containment system

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