Modems are devices that transmit an analog signal across telephone lines to another modem, often at much higher speeds than the previous technologies, to create a digital signal for transmission over telephone lines. The term “modem” is an acronym for modulator-demodulator. They are also known as transceivers because they can switch between sending and receiving signals. This means that your computer will appear to have several different adapters or cards with slightly varying properties, but they all perform the same basic functions.

How Does It Function?

1. Acts as an Interpreter 

A modem can act as an interpreter to translate communications between two different interfaces, such as serial and parallel. The most common example is the fax modem, which receives a digital signal from a computer and converts it into an analog signal for transmission over the telephone line.

2. Establish Connection for the Internet

The modem creates a WAN (Wide Area Network) connection between your workplace or home and the Internet. Every modem is assigned to a unique public IP address. This public IP address works as a modem identifier over the Internet.

This Internet connectivity can be established in several ways. You can either use a satellite or a dial-up phone connection or a DSL or a coax cable to establish the connection. Via an Ethernet cable, the modem can also be directly connected to the computer to create a physical Internet connection or connect the modem to the router to establish a Wi-Fi connection. 

A different modem type is available for each type of service. However, these modems are not interchangeable.

3. Correcting Errors and Controlling the Flow and Size of Data

Modem’s function does not only include modulation and demodulation. It is also responsible for correcting data errors and controlling the size and flow of data sent to/receive from the network. If the information retrieved from ISP does not match your devices’ values, the modem will send the data back. It also informs your devices when to send data, how fast data transfer, and how much data to send. 

4. Adjusting the Speed of Transmission

Modems vary in speed. They can either be fast or relatively slow. The speed is measured in bits per second (bps) and relates directly to how much data can be sent at one time. For example, a 1.5Mbps modem transmits data at 1,500,000 bits per second. Also, unlike most devices that adjust their speeds depending on connection quality, modems rely on an external source of power to adjust speed. This external source is transmitted through the telephone line.

5. Sending and Receiving Data

Modem’s primary function as a device is the implementation of the “data” channel. In other words, it controls or manages the flow and size of data sent to/from your computer to the rest of the Internet. Basically, the modem is responsible for communicating data from a computer to a telephone line. If a modem is equipped with a cable box, it will also manage cable-based devices such as cable modems and cable TV set-top boxes.

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A modem is a device that connects your home to the Internet Service Providers (ISPs), usually via a cable. Modems can be directly connected to a computer or routers to establish Internet connections. 


Q. Can I get Internet without a modem? 

A. No. Although some devices and services can provide Web access without a modem, they do not require one. If you do not have a modem, you will need to use the Internet Service Provider (ISP) to acquire Internet access instead.

Q. What is an Ethernet cable? 

A. Ethernet cables are also called LAN cables. They are used to connect your computer to the Internet through a router (also called an access point). By connecting the Ethernet cable to the modem (or directly to the computer itself), you can share files with others on your network or use an external hard drive.

Q. How do I update the modem’s software? 

A. In most cases, your ISP does not provide a new version of the software for your modem. This is because they usually rely on 2nd-party companies to provide updated software versions for their modems. As a result, you will need to consult your ISP or computer manufacturer for new versions of the modem’s firmware. The process is different from one company to another; however, most manufacturers have detailed instructions on updating the firmware on your modem from their website.