What is Modem: Types and Characteristics

A modem is a type of network device that helps devices in getting connected with internet. It converts digital data in a suitable format for analogue transmission. This device has different types that can be installed according to the your data requirement.

In this article, we will learn what is modem in computer network. We will also learn about these network devices in detail. We will learn about the different modem and its types that have been in use from past till the present times.

Table of Contents

• Define Modem in Computer Network
• Working
• Characteristics
• Types
• Applications of Modem
• Speed of Modem
• Advantages of the Modem
• Disadvantages of Modem
• Future Trends

What is Modem?

A modem is a type of network device that modulates and demodulates analog carrier signals to encode and decode digital information for processing. Modem is a hardware that transmits the data by modulating carrier wave signals to encode the digital information. The receiver will demodulate the digital signal for recreating the original digital information. 

Modems are classified according to the maximum data (bit/s) that they can send in a given time period. These are the variable-rate due to which they can be used over a medium that has less than ideal characteristics. 

While choosing a modem, you have to consider the following:

1. Is data transmission through the chosen modem secure?
2. What is the upload and download speed of the modem?
3. How much is the cost of the modem? Is it affordable or expensive?
4. What is the modem’s compatibility with the connected devices?

How does a modem work?

• Whenever a user uploads data from a computer on the internet.
• The modem takes in the digital signal from your computer and then, converts these signals into analog signals.
• Analog signals can be easily accessed by telephone networks.
• When computers try to download data from the internet, the modem takes the analog signal over the telephone and converts that signal into a digital signal. The digital signal is accessible by the computer.

Characteristics of a Modem

The following points highlight the characteristics of a modem:

1. Modems are useful in converting digital signals into analog signals.
2. They help in connecting the devices to the internet.
3. Only a limited number of systems can be connected to the internet through a modem.
4. Modems are prone to cyber-attacks which reduces the probability of secure transmission. 
5. The cost of a modem is dependent on the number of features it offers. More inclusion of features will lead to an increase in the cost of modem. 
6. Modems slow down when it is connected to a hub.
7. They are unable to track traffic between the LAN and the internet.
8. Modems require RJ11 Jack to communicate with telephone lines and RJ45 for connection with computers.
9. For modems to work, device drives must be installed in the operating system for configuration and communication. 
10. These devices must be configured with an Internet Service Provider (ISP) and computer for using the internet. 

Types of Modem

There are following different types of Modem:

1. Cable Modems

Cable modems help in establishing communication between computer and ISP over landline connection. These modems allow the access to high-speed data with the help of a cable TV (CATV) network. Such modems are external devices connected to your PC with the help of a standard 10 BASE-T ethernet card and twisted pair wiring. 

2. Telephone Modems

These modems are network devices that allow data communication between two computers over voice-grade telephone lines. Telephone modems convert bits to analog signals for transmission through physical channels. These also convert the analog signals in the local loops into bits that are understandable by a computer.

3. Dial modems

These modems convert the data between analog form (used on the telephone lines) and digital form (used on the computers). These networking devices plug into the computer at one end and a telephone line at another end. These modems can transmit the data at a maximum rate of 56000 bits/sec. Whenever you have connected to a network with the help of dial up modem, it relays distinctive handshaking sounds between the remote modem and your device. This sound helps in verifying if the connection is working. 

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4. Satellite Modems

These modems provide an internet connection with the help of satellite dishes. They transfer input bits into output radio signals. It then executes the vice versa. These modems are more reliable for providing an internet network in comparison with other modems. 

5. Digital Subscriber Line (DSL)

DSL are used for transmission of the digital data over telephone lines. These modems offer high-speed internet connection through telephone lines. Two types of DSL modem include asymmetric and symmetric DSL that use existing telephone wiring within your home wiring. Due to the use of existing wiring, these modems are cost-effective. 

Applications of Modems

Initially, these devices were used for either sending faces or for connecting the user with the internet. These days, modems have more than just two applications. These include the following:

1. Data transfer: Dial modems provide secure connections for smoothly transferring the data. These come along with the redial functionality in case a call is dropped. 

2. Reliable backup: Modems act as a backup in the absence of stable broadband or server connection. With modems, data can be retrieved and servers can be configured even if the status of the broadband connection is not known. 

3. Remote management: These networking devices can be installed at remote or sensitive locations. Along with that, modems help in remotely controlling certain applications. This helps in a quick resolution to issues that will otherwise require physical assessment.  

Speed of Modem

Classification

We often describe modems by how much data they can send in a set time. We measure this in bits per second (bit/s or "bps"). Sometimes, but not often, we use bytes per second (B/s). For newer, faster broadband modems, we use megabits per second (Mbit/s).

Historical Measurement

In the past, people also described modems by their symbol rate, measured in baud. Baud means symbols per second, or how many times a modem sends a new signal each second.

For example:

• The ITU-T V.21 standard used two different frequencies to represent two symbols (or one bit per symbol). It sent 300 bits per second using 300 baud.
• The first ITU-T V.22 standard could use four different symbols (two bits per symbol). It sent 1,200 bits by using 600 symbols per second (600 baud).

Variable Rates

Many modems can change their speed. This helps them work on less-than-perfect connections, like poor quality or very long telephone lines. Often, modems can figure out the best speed on their own. They might do this when first connecting or while they're working.

Advantages of Modem

The following are the advantages of a modem:

• A modem can convert a digital signal into an analog signal.
• LAN can be connected to the internet via Modem.
• The modem can simultaneously perform modulation as well as demodulation processes.
• It can work with various types of networks including cable, fiber and phone lines.
• Wired connections through modems offer more stable connections as compared to wireless.

Disadvantages of Modem

A Modem has the following disadvantages:

• A modem will be slowed down when it is connected to the hub.
• It is not possible to track the traffic between the internet and the LAN through Modem.
• Only a limited number of devices can be connected to the internet using a Modem.
• Modems are susceptible to security-related attacks.
• Maintenance of traffic is not possible through Modems.

Future Trends and Advancements in Modems

Based on general trends in technology and networking, we can anticipate that:

• Gigabit-Speed Modems: As internet speeds continue to increase, we can expect to see more widespread use of gigabit-speed modems. These modems will be able to handle higher data rates, providing faster and more reliable internet connections.
• Integration with Next-Generation Networks: With the advent of 5G and beyond, modems will likely need to be able to integrate with these next-generation networks. This could involve supporting new frequency bands, handling higher data rates, and possibly integrating with other types of networks (such as satellite or fiber optic networks).
• 5G and Beyond: As 5G networks become more widespread, modems will need to be able to support these networks. This could involve supporting higher data rates, lower latency, and more reliable connections. In the future, we may even see the development of 6G or 7G networks, which would require further advancements in modem technology.

Conclusion

We hope that through this article on what is modem and its types, you have been able to understand what is modem and where it finds applications. There are different modems with different characteristics. You should choose a modem based on your speed and internet requirements.