What is a modem definition? What is a modem in simple words

Today, many technical terms have entered our everyday speech, the meaning of which is sometimes poorly understood by people who are far from the problems associated with electronic technologies.

One of these concepts is a modem, a device that you may have or need in order to constantly have. Let's figure out what a modem is and how it works.

The word “modem” is an abbreviation or acronym formed from two words: “MODulator-DEMOdulator”, which describe the functions of the device in a language understandable to specialists. That is, using a modem electrical signal, going in one direction is modulated, and coming back is demodulated, and thus the computer is connected to the Internet.

Modems today are widely used in various fields of activity where accurate and often secure system data transfer. Everyone knows, in addition to computer modems, telephone modems. These devices are used in military affairs, providing communication between command posts and tracking devices, military units, etc.

In fact, any modem is a device that converts a computer binary code into analog oscillations electrical voltage(in a telephone modem) or into radio waves (in a modem demon wired communication), if your computer sends a data packet, and the reverse conversion if it receives data from the server. This allows for high data transmission accuracy and communication quality, since the digitized signal is transmitted with significantly less interference than an analog signal.

By design, modems are:

— external – in a separate case, with its own power supply and connection to a computer via a COM port;

- built-in - which is a board located inside the computer;


- software, or card - having only a signal conversion device, and its processing is performed by the computer processor. These modems are connected via USB input.

Based on the principle of data transmission, there are several most common types of modems today.

1. A telephone or dial-up modem transmits information to the Internet using a wired telephone line, and at the time of transmission the telephone signal cannot be transmitted.

2. The ADSL modem transmits information over the telephone wire, but does not interfere with the passage of telephone signals.

3. USB modem – small external device, connected via USB port and transmitting information using cellular networks.

4. 3G modem – today provides the fastest mass data exchange using 3G technology. In order for the 3G modem to be used, a 3G cellular communication system is required.

Experts advise: if your Internet connection via a modem is lost, you need to follow these steps sequentially:

1. Check if the modem is connected to the computer.

2. Check if there is a network reception signal.

3. Check whether there are enough funds in your account to pay for the Internet connection.

4. If all of the above points have been completed and the reason for the lack of signal has not been found, you should call your provider and report the problem. Often it can be eliminated without a technician visiting it by changing the modem settings.

Often, non-specialists confuse a modem with a router, but this different devices. If the modem is used to convert the passing signal, then a router is needed to distribute the incoming signal to several devices.


Modern routers include both a modem and a router, so the router is a modem of a sophisticated design. It receives a signal from the server, sorts it and sends it to the computers, tablets or phones connected to it, each device receiving a data packet intended for it.

Using a router, we have the opportunity to connect several different computers and work on each of them offline.

IN modern world Internet users receive information, explore the Internet space, without thinking about how they can do this. Almost always, users confuse a router with what is a modem. Let's look at what it is in this article.

The ancestor of the current data device appeared in 1962. His the creator is AT and T company. At that time, the speed of information exchange was only three hundred bits per second. Then in 1991 this data increased to fourteen kilobits per second.

What is a modem

A modem is a device for receiving and sending information through the system telephone communication. Streams of information enter it, where they are converted into the necessary signal that passes through the telephone line. It goes to the other end of the wire, where another similar device is already demodulating the signals, turning them into computer signals, and they enter the computer, and then are displayed on the screen user. The word itself comes from an abbreviation of two English words: modulator and demodulator.

What are these devices for?

Modems are in use for connection with the Internet via a telephone line. This device is a kind of bridge between the Internet and home or office equipment. Modern models can be used as a router, sharing the Internet between several devices.

It is worth noting that it will not be able to fully replace the router, since it is not possible to receive the Internet via rj45 from the provider.

Types and types of modems

All such gadgets can be conditionally divide by types and types. Let's look at them more specifically:

• By type of connection modems are made wired and wireless. Wireless well used by laptop owners. Since they connect to the laptop via a USB connector.

Wired connected to the computer using a cable.

• According to the operating principle divided into hardware and software. Hardware differ from software ones in that all signal processing functions are performed by the device itself. Software They give all the work to the computer processor.
• By type of connection devices are divided into telephone, mobile, Dial Up. Analog modems or Dial Up work over the telephone network. Their speed reaches only 56 kilobits per second. To replace analog gadgets ADSL technology has arrived and is now used everywhere. The transmission speed of information via ADSL reaches 100 MB/s. Mobile phones include those available in the form of a keychain. They work using EDGE, 3G, 4G protocols. Data transfer speed in 3G is up to 3.5 MB/s. While the speed of 4 G is 100 MB/s.
• Broadband. This ADSL modems. Today, the fastest devices for data transfer.

Popular manufacturers

Modems are produced by many companies. But the most popular of them are Cisco, Zixel, TP LINK, ASUS. These models are famous for being complete. Can work like router.

They are often equipped with DLNA, file and FTP server. In addition, they have an interface to support up to 4 computers. Web interface support.

What does a modem consist of?

Almost the only external hardware components are the input and output ports. This also includes universal, signal and modem processors, read-only storage, RAM, and device status indicators.

The functions that the device can perform are determined mainly by the activities of the universal processor and the program located in the ROM. If update ROM or reprogram it, you can improve the functions of a particular device.

The signal processor converts incoming and outgoing signals into those needed by the device that is connected to it. Buffered in RAM incoming and outgoing data, compression algorithms and other functions occur. Adapters allow you to exchange data, on the one hand, between the modem and the Internet line, and on the other hand, between the computer and the modem.

Operating principle

This device (regardless of that USB or stationary) turns normal signal to digital. This device has a built-in modulator that converts these signals. The modulator converts signals from the computer, before starting to transmit information, into the signals required by the Internet line. Then the data is transported. And the device at the other end is already demodulating these signals to those that are necessary for the PC with which it is connected.

This is how the information needed by the user is supplied.

What is the difference between a router and a modem?

Many people confuse a router with a modem. This not the same devices. Routers have the following features:

• The modulator-demodulator converts the signal, and the router divides it among network users.
• The first one works with one user, the router with several.
• A router, unlike a signal converter, is a multifunctional device.
• Routers are assigned their own IP address.

Although it is worth noting that for the most latest models such the differences are not relevant. Almost all functions of the router and modem are now identical, except that the router cannot transmit data through the telephone line. IN modern devices this can be considered the main and only difference.

Good day, my dear friends. Today I will share some nostalgia with you, remembering what a modem is. Oh, what a time it was... I feel that not everyone understands me now, especially young readers who heard the name of this device for the first time.

Then I explain by turning to history.

Let's say that you have a PC, but there is no Internet, none at all. Do you feel bad without him? Yes, especially considering that you know its endless possibilities. So here it is. In the 90s, computer owners in Russia for the first time learned about such a Wonder of the World as the global web. And it turns out that you can connect to it via a simple telephone network. Which was at that time the only means of wired communication laid even in remote villages.

But this required that there be a provider in your city that provides Internet access. And the user had a device called a modem that connected between the PC and the telephone line.

Where did it all start?

It just so happened that after the fall of the Iron Curtain, the Internet came to our country with ready-made hardware and software solutions. But in reality, both the network itself and the devices serving it had to go through a thorny path to finding optimal solutions.

The history of modem data processing begins in the post-war mountains in the United States. In 1950, a road was laid between military air defense bases located throughout North America, which connected radars, terminals, and command centers. Signal processing at the ends of the lines was carried out using modulating transformations.

This principle became the basis for the creation of similar devices for network communication between personal computers.

In 1979, Micromodem II appeared, intended exclusively for the Apple II PC. This is how the device got its name “modem”, derived from the name of the two operations it performs: MODULATION and DEMODULATION.

I will now explain the purpose of these functions and how they work. To impulses digital code, representing a “rectangular” graph, could be transmitted over a channel intended for audio communication; they are pre-modulated, after which the analog signal familiar to a telephone line successfully travels through the network.

In turn, the computer is not capable of perceiving anything unusual for it. analog information. Therefore, the smooth change in line voltage is demodulated back into pulses that can be read by the processor.

But if you study the operation of the modem in more detail, you should pay attention to its interaction with the network and PC, which implies a system of queries, recognition, changing connection parameters and other control operations.

All this is recorded specially program code. In 1981, Hayes introduced the Smartmodem 300. It used a system of such commands that later became a standard in the modem industry.

What types of modems are there and how they are designed

But, since we started to delve into such subtleties. Then I propose to immediately consider the modem device, consisting of:

• power supply unit;
• two connectors for connecting a telephone cable (incoming from the socket and branching to the telephone) and network LAN or sequential LPT port for connecting to a computer;
• controller responsible for exchanging streaming data from a PC;
• a signal processor that directly performs signal conversion operations;
• memory chipset including RAM and two types of non-volatile: ROM (with firmware, drivers) and NVRAM with working settings.

I’ll say right away that this “set” is taken from the design external modem, which were the most common during the period of their greatest popularity. Some people probably remember models such as Courier or Zyxel.

Over time, internal modems appeared that were inserted into the motherboard. They no longer required a power supply and an external com-port. But a connector was used that could be useful for other needs. Some manufacturers even made built-in modems integrated into the motherboard.

Connection method that determines Internet speed

A conversation about modems will not be complete if we ignore the methods for connecting them to the Internet. And the first, of course, is Dial-up - regular dialing, dialing a number. Of course, this function was performed by the electronic filling of the device, accompanying its work with characteristic sounds coming from the speaker. They were not specifically disabled (despite the annoyingness) in order to control the process. Dial-up connection had its own characteristics:

• dialing took for a long time, and while working on the network, using the phone was impossible;
• Very low speed connections 40 - 45 kbit/s, which, moreover, strongly depended on the quality of the telephone line;
• billing was often per minute, and taking into account slow speed- Expensive…

As an alternative, corporate and wealthy users were offered a dedicated Dial-up communication line. The advantage of which was the absence of dialing and best quality channel.

The practice of using the Internet has shown that the volume of information downloaded by a user is much higher than that transmitted to the network. Therefore, ADSL technology was proposed - asynchronous frequency division data streams using a multiplexer and a modem capable of working with such a signal. This provided new opportunities and obvious advantages:

• it became possible to simultaneously use the phone while working with the Internet;
• speed increased to 25 Mbit/s;
• Connection time has been significantly reduced;

Transferring information with help allowed us to take a fresh look at the possibilities high-speed Internet, but, unfortunately, the limiting factor at this stage was the capacity of telephone lines. Providers began to directly lay communication lines ( twisted pair or optical fiber) to the user, bringing the connection speed to 100-300 Mbit/s.

No longer relevant?

What about our modems, you ask, are they missing? Well, not really. Still, laying a new line is a troublesome task, and the telephone cable is already lying there. It would be a sin not to use it. Therefore, providers still offer this service. Another thing is that telephone communications have changed, digitized, become mobile and provided new prospects in the form of 3G/4G USB modems.

Now you can connect to the Internet anywhere within the coverage area mobile operator. Moreover, the data transfer speed will allow you to easily watch streaming video. Over time, USB modems have competitors - smartphones. Which, in capable hands, can easily distribute the Internet via wi-fi.

But that's another story. And I think it’s possible to finish this one. See you soon, my dear readers.

Every person has heard the word “modem”, but what does it mean? This device name comes from the abbreviation “modulator-demodulator”. Computers only perceive digital signals, and were initially received from telephone lines in the form of analogue ones. Modems have 2 interfaces with clear purposes. The first has a digital output and is connected directly to the system unit or inside it. The second has a socket for connecting a standard telephone cable with a plug.

The modem itself includes processors responsible for receiving and processing the signal. Actually, they are responsible for converting the signal into the desired one and there is also RAM and ROM.

A little history

Modems began to be used in air defense systems in the United States in the 50s. They represented the unit at various bases, air forces, radars, and command centers. This was a more reliable encrypted communication than telephones. After all, not everyone could modulate and demodulate signals. Micromodem II is considered to be the first modem for PCs. It was released for Apple and had a speed of 110/300 bps. Nowadays this speed is considered to be a snail's pace, but at the time of the birth of information transmission over long distances it was considered quite good.

Modem types

Internal modems. Inserted into system unit computer mainly into the PCI slot. There were others, but this one is the most popular. The advantages are that he was neither visible nor audible, he was distinguished by his invisibility.

External modems. Usually they had their own power supply, so the computer system unit remained at its own power consumption. We connected to old COM ports, USB or fairly new Ethernet. Some modems were powered via a USB port, fortunately the voltage required was low. All of them had external LEDs, by which one could judge the connection status.

Built-in modems. Could be built into motherboard, but were more often used on laptops. Very few such devices were used.

Internal structure

Input or output ports. Solutions technical diagrams intended for confident reception signal from the telephone network and transmitting it to a computer in decrypted form. It also works in the opposite direction.

Signal processor. Encrypts its data transmission and decrypts it based on the transmission protocol.

Controller. Manages data transfer and encryption. As the name suggests, it controls the operation of the systems it owns.

Built-in memory. RAM. Familiar to everyone RAM where file compression and management takes place correct algorithms work. ROM - Power-independent memory, known as firmware.

This is a program that has all the necessary operating algorithms and exchanges data with a computer.

Operating principles

• Hardware. Any operations related to receiving, decrypting or sending a signal to its destination took place inside the modem, using only its computing resources.
• Program. All kinds of operations for encoding or decoding signals from other devices took place inside the computer, and depended only on its computing abilities and speed. The modem only converted the signal into the correct one, having a microprogram in its assets.
• Semi-programmatic. Reminded me of all of the above. The work was mostly done by the computer; the modem was connected while executing protocols high level and launching a special driver.

Connection and Connection

• Telephone. They became most widespread in the late 90s and 2000s. There are 2 types of communication here - ISDN. For telephone lines using connection switching - DSL.
• Cable. Special cables are used to transmit and receive data.
• Radio. Radio data exchange is carried out only on specially designated and unused radio frequencies.
• Satellite. Used for long distance transmission. Radio frequencies are also being used, but with signal transmission through artificial satellites planets.
• Wireless. Use the same frequencies and protocols as cellular communication. You can name the well-known GPRS, 3G, Edge and Wi-Fi. Everyone knows cellular companies they sell 3G modems that can look like a small flash drive and be inserted into a free USB port. Despite their small size, they receive and transmit encoded signals quite well. But only where there is a reliable connection to a cell tower.

The Internet has taken over everything modern society. There are no longer any places in the world where there is no possibility of using it. Personal computer and there is a laptop in every home. Computer skills - mandatory requirement when applying for a job. Even printed products (newspapers and magazines) fade into the background, giving way to news portals online. Most Internet users have heard of modems. Many people have had to use them. But not everyone knows about the types of modems and the principles of their operation.

Modem and its functions

The main function of the modem is to ensure communication between devices during data exchange. If we talk in simple words, then this device is designed to encode, transmit, receive and convert signals. The areas of application of such devices are very wide: they are used in civil and military communications. Among ordinary consumers, the most popular are modems, which are used to provide an Internet connection. Let's take a look at how they work.

The most popular among users are modems that provide Internet access.

How the modem works

Initially, such devices were used to create computer networks through the use of telephone lines. All information processed in computers is in digital form, and is transmitted via telephone cable in the form analog signal. Therefore, devices were needed that could connect PCs at different ends of the line.

The word "modem" is a derived form of "modulator-demodulator". Before transmitting data, it transforms the signal into a form that meets the requirements of the communication channel used (it modulates the signal), and changes the received signal into a form suitable for processing by the user’s computer (it demodulates the signal).

The modem is used to transform the signal into a form suitable for processing by a computer

History of the device

Digital modems arose from the need to transmit data between air defense units in North America. Mass production of modems in the United States began in 1958, primarily for the Sage air defense system (the first time the term "modem" was used). The devices were used in networks connecting terminals at various air bases, radar sites and command and control centers scattered throughout the United States and Canada.

The first representative of Bell Dataphone 103 devices was released in 1958, its data transfer speed was 300 bps. The AT&T telephone company introduced dataphone service (the company provided information transmission via telephone channels). The Bell 212a modem, released later, allowed data transmission at a speed of 1200 bps, but it was characterized by increased sensitivity to telephone line noise. The modem developed by Racal-Vadic turned out to be more resistant to noise. From that moment on, competition began for standards and rights in this industry.

The modem is used to transform an analog signal into a digital one

Modems have become widespread since 1977, when Dennis Hayes and Dale Hethertington released the 80-103A model. By the mid-2000s, modems became part of the computer, helping it turn into a multifunctional device that provides the user with the opportunity to receive information from around the world. Modems made individual computers parts of a global network.

Types of computer modems

Internet technologies have undergone significant development. The telephone cable can no longer cope with the required volume of data transfer. New types of modems have appeared with various functions and with in different ways connections. A huge number of devices are produced, differing in areas of application and operating modes.

Any classification for modems can only be a conditional division. First of all, you need to determine what the modem is for. There are devices that provide work on a desktop computer, providing access to the Internet for all devices using Wi-Fi networks, and compact portable models that can provide Internet access anywhere with network coverage.

By method of execution

Depending on the methods of application and their operating conditions, modems are used, which can be divided into separate groups:

• external - are standalone devices, which can be connected to a computer and other equipment;

  An external modem that receives power from the in-house electrical network

• internal - are, in fact, an expansion card;

  The internal modem is an expansion card installed in the computer

• built-in - are the internal part of devices such as a laptop or computer. These modems cannot be removed, they can only be disabled;

  The built-in modem is an integral part of the device

• Portable modems are designed for use with mobile devices. Their distinctive feature is their small size, but at the same time full functionality, not inferior to other types of modems;

  Portable modems serve to provide mobile access to the Internet

• group - a set of individual modems assembled into a unit with a common power supply and control device. Refers to professional modems.

  Group modems are classified as professional modems

It must be remembered that internal modems are an integral part of devices, and built-in modems are installed as additional equipment.

By connection

Based on the connection method, modems can be divided into three categories:

• modems connected to USB, COM or Ethernet ports of a computer. These include devices with externally connections;
• devices installed inside the computer in one of the PCMCIA, PCI, ISA slots;
• modems that are structurally part of other devices.

By type of supported networks

Depending on the type of networks in which they are used, they are produced various types modems. They can be divided into several categories.

Previously, modems were most often used to provide communication via telephone cables. Now, due to the development of wireless methods for connecting computers, compact USB modems are the most popular. With their help, high device mobility is achieved. Sales of such products on world markets are constantly growing. The majority of modems (82%) used by owners of laptops, computers and various mobile devices, constitute modems connected to USB ports.

Table: types of modems by type of supported networks

Popular modem manufacturers

Since 2009, the main roles of modem manufacturers in the market have been Chinese companies. Huawei company occupies 45% of the global USB modem market, its competitor ZTE has 21%.

The list of device manufacturers is very large. The most popular now are:

• Zyxel;
• D-Link;
• USRobotics;
• Acorp;
• Tenda;
• Cisco.

The range of modems is constantly expanding:

recently appeared on the market new look modems. They help provide Internet access to all surrounding devices that can use Wi-Fi networks. Such a device is the Mi-Fi model manufactured by Novatel;

The Mi-Fi modem performs the functions of a portable (mobile) router

modems are no less popular ZyXEL Keenetic DSL. They provide a standard Internet connection using wires and allow you to set up a Wi-Fi network, which provides Internet access to all home devices. Convenient for use both at home and in the office;

The ZyXEL Keenetic DSL modem will provide Internet access to all devices in your home Wi-Fi networks

Particular attention can be paid to the ASUS DSL-AC52U model. It provides support for everyone mobile operators. The use of the device guarantees uninterrupted access to the Internet, which is achieved due to the ability automatic switching between different networks;

The ASUS DSL-AC52U modem guarantees Internet availability due to the ability to switch between operators

Constant access to the Internet will be provided by the compact and convenient Huawei E3372h;

The Huawei E3372h modem will provide Internet access within the coverage area of ​​the mobile operator

Selecting, connecting and setting up an ADSL modem

Most often when connected to telephone networks ADSL modems are used.

Most cheap option connection - a modem equipped with a USB interface. Such devices are small in size and easy to set up. Unfortunately, not all computers are compatible with such modems.

Modem with USB interface is easy to use

Modems equipped with an Ethernet port are universal and connect to all computers and laptops. If you intend to use desktop computer, and there is no need to create an internal Wi-Fi network, it makes sense to choose such a device.

Modems with Wi-Fi are the most popular. They provide for connecting devices both wired and wirelessly. Such a modem can work as a bridge or router. It provides Internet distribution via Wi-Fi network. Exactly like this multifunctional devices worth choosing to use. Main criterion estimates when choosing them are the power you need. The price of the modem and coverage area depend on it Wi-Fi signal. Accordingly, for small rooms more than enough cheap option, in case of requirements for covering a large area, it is necessary to select a higher power.

A Wi-Fi modem will help you create a home network

To configure similar devices Information from the provider is required - DNS and IP address, PVC, login and password assigned to the subscriber. These parameters are entered manually. Many operators provide a disk with the necessary settings. In such cases, special knowledge and skills are not required to configure the modem.

If the modem has been used before, the best solution will reset its settings to factory settings. This function is mainly used when changing providers or in case of losing the access password.

To return the settings to the default ones:

1. Connect the ADSL modem to a power source.
2. Find a button or hole (depending on the model) labeled Reset on the modem body.
3. Press the button for about 30 seconds.
4. If a hole is provided in the device for these purposes, you need to insert a thin metal object such as a paper clip into it and hold it there for some time.

If the manipulations are performed correctly, the device will reboot and return to factory settings.

Directly connecting the modem is done in the following way:

1. Connect the modem to the power supply.
2. Connect the telephone cable to the modem.
3. Connect the Internet cable leading to the computer to the LAN connector.
4. If the modem can distribute Wi-Fi and your device is equipped with a Wi-Fi receiver, you do not need to connect the cable. Find the network on your device and enter the password specified in the instructions for the modem.
5. At correct connection The network indicator that the modems are equipped with should blink.

Setting up a modem usually does not raise questions even for the most inexperienced users, if there is installation disk. Everything happens automatically.

Video: how to set up an ADSL modem

Selecting, connecting and setting up a 4G modem

There are a number important indicators, which you need to pay attention to:

• the speed with which information is processed and received;
• presence of a slot for connection outdoor antenna, internal antenna power;
• the number of consumers who can simultaneously connect to the modem;
• models of modem-compatible routers;
• the ability to automatically switch between different networks.

The most popular are 4G modems with a USB interface. They are convenient due to their versatility; they can be used with any device: tablets, laptops, computers with operating systems Windows systems 7, 8, 10 or Android. Comparison technical characteristics will help to do right choice devices. It is advisable to choose a modem that has a warranty and official center service. You need to purchase the device from trusted sellers.

Installing and configuring a modem is usually not difficult; the system carries out all actions in automatically. Let's consider connecting the modem to the Megafon 4G router:

1. Insert the modem with the SIM card into a free USB port on your computer or laptop.

   The modem must be inserted into a free USB port

2. After the system detects the device connection and opens the autorun window, click on “Run”.

   In the autorun window that opens, click “Run”

3. After this, the process of preparing the driver installation will begin.

   You need to wait until the preparation process for installing drivers is completed

4. Click the install button in the Megafon Internet window.

   To start installation software modem, click the “Install” button

5. Wait for the process to complete.

   Wait until the modem software is installed

6. After installation is complete, the system will notify you that a network has been detected.
7. Will happen automatic start programs. In the window that opens, click the “Connect” button.

   In the window that opens, click the “Connect” button

8. If you successfully connect to the Internet, the “Disconnect” item is activated in the “Modem” section.

   In the “Mode” parameter, select “Automatic selection”

9. The “Statistics” tab will help you monitor the speed of sending and receiving data, and control the remainder of the allocated traffic.
   

   Using the “Statistics” tab, you can control the data transfer speed and the remaining allocated traffic

Does Internet speed depend on the modem?

In reality, the speed of the device depends on the capabilities of the provider. However, each modem model has its own throughput, which also has a strong influence on this indicator. Estimated throughput capabilities are usually indicated in the accompanying documents for the equipment.

But we shouldn’t forget about factors such as the number of end consumers using the Internet or system load various programs, working in background. In addition, providers do not always provide the declared indicators. Don’t forget to timely optimize your system, update your antivirus software, and periodically clean your computer with utilities such as Glary Utilities.

Of all the variety existing types and types, the most interesting for ordinary users are modems that provide wireless access to the Internet from anywhere in the signal coverage area. As the capabilities of cellular operators grow, this method of connecting to the network is gaining popularity. Soon the speed wireless internet equals the capabilities provided by high-speed cable connections.