What is Modem in Computer Networks? Types of Modem Explained

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You have heard about the modem and most probably the dial-up modem if you have taken dial-up internet services in the past.

The technology has evolved, and you would be using a broadband modem or integrated modem, which provides a seamless internet connection.

But, what is a modem in computer networks, and how does the modem work. Further, we will explain the type of modems based on the internet connection.

What is a modem in computer networks?

A modem is a networking device that converts digital data into a signal transmitted or received through a phone line, cable, and satellite connection.

Moreover, a modem is also referred to as an asynchronous device, transferring data into small packets.

The packet received at the other end will get reassembled in the form that the computer can use.

Before, data transmission takes place over telephone lines, which is the only way to access the internet.

In such cases, the modem converts data from analog to digital for two-way communication.

With the availability of high-speed digital modem in today’s world, it doesn’t require analog to digital conversion.

The term modem is formed by combining the two processes: modulation and demodulation.

Let’s look into the differences.

Difference between modulator and demodulator

The modulator is a process to convert information from a digital signal into an analog signal at the transmitting end.

On the other hand, the demodulator is a process to convert information from an analog signal into a digital signal at the receiving end.

Brief History of Modems

The first modem was known as Dataphone, which AT&T released in the year 1960.

When the first modem was developed, the digital data need to be converted into analog signals to get transmitted or received over telephone lines.

Back then, the speed of the internet is measured in Baud. But, as the technology improved, the internet speed is then measured in bits per second.

The first commercially launched modem supports an internet speed of 100 bps, and it was used by the U.S. Department of Defence, news services, and some large companies.

Later on, in the late 1970s, the modem becomes famous for home users.

When the World Wide Web was introduced and become famous, then the dial-up modem is the primary way to access the internet.

Later on, the dial-up modem users shifted to the broadband modem because of fast speed and advanced technology.

Types of modem connections

Dial-up Modems

As mentioned earlier, dial-up modems are one of the oldest methods to access the internet.

The dial-up modems convert the data from the analog form, which is used in the telephone line, to digital format, which is used and understood by computers.

The dial-up modes are divided into two types: external dial-up modems and internal dial-up modems.

The external dial-up modems are devices connected to the telephone line, and the other end is connected to the computer.

The internal dial-up modems are those which is integrated within a computer or device by the manufacturer.

As the dial-up modems are upgraded with advanced technology, now it can transmit data to the maximum rate of 54 kbps.

But, some public telephone lines are still putting restrictions on dial-up modem data rates, because of which they can have a maximum of 33.6 kbps speed rate.

When you use a dial-up modem to connect with the internet, you hear a dial-up tone similar to dialing a phone number.

Further, the squealing sound on the dial-up modem will let you know that the internet connection is in the process.

Broadband Modems

Broadband modems use advanced signaling techniques, compare to a dial-up modem, to achieve higher network speed.

This type of modem is used by DSL (Digital subscriber line) and cable internet.

The external broadband modems plug one end to the router or gateway device, and the other end is connected to the cable line.

The router or gateway device directs the signal to all the devices in a home network.

Moreover, the most router comes integrated with the modem as a single external device to access the internet.

However, the modem is also supplied by most of the internet providers free of cost as part of the package, or it may cost as a monthly fee.


Both the internal (integrated) and external modem can be used to access the internet. The type of internet services includes dial-up, cable, and DSL internet.

Whereas fiber-optic technology doesn’t require a modem for the supply of internet services.

Nowadays, the modem and router combo is fairly common to provide a wireless gateway to all network devices. So, there is no need to buy a modem and router separately.