Regular modem. What types and types of modems are there?

Modem (an acronym made up of the words modulator-demodulator) is a device used in communication systems and performs the function of modulation and demodulation. The modulator carries out modulation, that is, changes the characteristics of the carrier signal in accordance with changes in the input information signal, the demodulator carries out the reverse process. A special case of a modem is a widely used peripheral device for a computer that allows it to communicate with another computer equipped with a modem via telephone network(telephone modem) or cable network(cable modem).

Modem types:

By execution:

External - connect to COM or USB port, usually have an external power supply (there are USB modems powered by USB and LPT modems).

Internal - installed inside the computer in an ISA, PCI, PCMCIA, AMR, CNR slot

Built-in - These are the internal part of a device, such as a laptop or docking station.

According to the principle of operation:

Hardware - all signal conversion operations, support for physical exchange protocols, are performed by a computer built into the modem (for example, using a DSP, controller). The hardware modem also contains ROM, which contains the microprogram that controls the modem.

Winmodems are hardware modems that do not have ROM with firmware. The firmware of such a modem is stored in the memory of the computer to which the modem is connected. It works only if there are drivers, which were usually written exclusively for operating systems of the MS Windows family.

Semi-software (Controller based soft-modem) are modems in which part of the modem’s functions are performed by the computer to which the modem is connected.

Software (Host based soft-modem) - all operations for signal encoding, error checking and protocol management are implemented in software and are performed central processor computer. At the same time, the modem contains analog circuit and converters: ADC, DAC, interface controller (for example USB).

Type:

Analog - the most common type of modem for regular dial-up telephone lines

ISDN - modems for digital dial-up telephone lines

DSL - used to organize dedicated (non-switched) lines using a regular telephone network. They differ from dial-up modems in the coding of signals. Typically, they allow simultaneous data exchange to use the telephone line as usual.

Cable - used to exchange data over specialized cables - for example, through a collective television cable using the DOCSIS protocol.

Main article: Wireless modem

Satellite

PLC - uses technology for transmitting data over household wires electrical network.

The most common currently:

Internal soft modem

Modems built into laptops.

External hardware modem

Basic elements of a modem

I/O ports are circuits designed to exchange data between the telephone line and the modem on the one hand, and the modem and the computer on the other. A transformer is often used to interface with an analog telephone line.

Digital Signal Processor (DSP) Typically modulates outgoing signals and demodulates incoming signals digital level in accordance with the data transfer protocol used. May also perform other functions.

The controller controls the exchange with the computer.

Memory chips: ROM - non-volatile memory in which the modem control firmware is stored - firmware that includes sets of commands and data for controlling the modem, all supported communication protocols and interface with a computer. Updating the modem firmware is available in most modern models, for which it is used special procedure described in the user manual. To enable flashing, flash memory (EEPROM) is used to store firmware. Flash memory allows you to easily update the modem firmware, correcting developer errors and expanding the capabilities of the device. In some models of external modems, it is also used to record incoming voice and fax messages when the computer is turned off.

NVRAM is a non-volatile, electrically reprogrammable memory that stores modem settings. The user can change settings, for example using a set of AT commands.

RAM - RAM modem, used to buffer received and transmitted data, operate compression algorithms, etc.

Modems with additional features

Fax modem - allows the computer to which it is connected to send and receive fax images to another fax modem or a regular fax machine.

This allows you to:

Using such a modem in answering machine mode and for organizing voicemail.

Story

AT&T Dataphone Modems in the United States was part of SAGE (System Air Defense) in the 50s. It connected terminals at various air bases, radars and control centers with command centers SAGE, scattered throughout the United States and Canada. SAGE used dedicated communication lines, but the devices at each end of these lines were the same in principle as modern modems.

The first modem for personal computers was a device from Hayes Microcomputer Products, which released the Micromodem II for personal computers in 1979. Apple computer II. The modem cost $380 and operated at a speed of 110/300 bps.

In 1981, Hayes released the Smartmodem 300 bps modem, the command system of which became the de facto standard.

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 are a mandatory requirement when applying for a job. Even printed products (newspapers and magazines) fade into the background, giving way to online news portals. 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 different ways connections. Available great amount devices that differ in application areas 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 board;

  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 distinguishing feature- small dimensions, 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 - set separate 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 different kinds 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 it is achieved high mobility devices. 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 occupies 45% of the global USB modem market, while 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 the new kind 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

no less popular ZyXEL modems 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;

Modem ZyXEL Keenetic DSL 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 provide a 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

ADSL modems are most often used when connecting to telephone networks.

The cheapest connection option is 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. These are the kind of multifunctional devices that you should choose for 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 a cheaper option will suffice; in case of requirements for covering a large area, it is necessary to choose a higher power.

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

To configure such 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 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;
• number of consumers who have the opportunity to simultaneous connection 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 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 capacities are usually indicated in accompanying documents to 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, similar method Internet connectivity is gaining popularity. Soon the speed wireless internet equals the capabilities provided by high-speed cable connections.

The Internet is developing very quickly. The rest of the technology is also developing rapidly. Now every device is able to access the Internet, if only it were possible. And she is. Now even in public transport You can download web pages via Wi-Fi.

To access the Internet there are special devices- This router or modem. In this article we will analyze the differences between these devices and also find out whether these two devices can be used.

Description of the modem and router

First you need to understand the concepts. Let's start with the modem. This device is responsible for modulating or demodulating the signal it receives. In simple terms, the modem receives and converts data that comes from the network. He does this in such a way that any gadget can understand it, and then utilizes it for packet data exchange. This device provides Internet access to only one gadget.

There are several types of modems. They depend on the connection method and the method of receiving data:

• Stationary modem. For connection use special cable, through which decoded data is received and transmitted.
• Mobile. It differs in that a USB port on a computer or laptop is used to transfer data. No wires are required for connection.

A router is a device, which is capable of distributing traffic among several network participants. This device does not have decoded data. The router is designed to distribute the signal between several participants in the same network, as well as to regulate its operation.

At the same time, the modem is also responsible for processing and receiving the signal. Most models have a built-in modem. Even if you buy a router at a low price, it will still have a modem inside. Thus, you can connect to the network either directly via cable or use a Wi-Fi connection. Everything will depend on the provider and the connection option.

These two devices differ significantly from each other. The router is distinguished by the fact that It has own IP address. The router also provides network connectivity to multiple devices at once. As for the modem, it can connect only one gadget to the Internet. His main task is to provide a signal only to the object that is connected to it. The modem only works with one client.

The router has more functionality. It creates a signal for multiple participants. You can connect from any gadget: smartphone, computer, laptop, tablet (wi-fi). It has its own IP address, which can be assigned to any network participant.

The modem only converts the signal according to its means USB cable and radio waves. Such a device is limited in capabilities, the tasks of which are minimal. The router configures the network depending on the user's requirements. A router can improve connection security and data security. You can also configure traffic through this device.

If the modem does not work in tandem with the router or is not built into it, then it is best to choose a router. It is more convenient for families, as it allows several users to connect (works via wi-fi). It is worth noting that providers are now releasing routers with a built-in modem. That is, you can connect to the network directly, you can use a wireless network.

Routers with built-in modems have already appeared on the market. The most common models are:

By purchasing one of these devices, you can connect to the network in two ways: via wi-fi or via 2G/3G. There are router models that allow the Internet to be used only by the user who is connected to this network via a USB port. If the connection is via 3G, then other users can connect to the network via wi fi.

The prices for such devices vary - from 1200 to 9000 rubles.

Before buying a router with a built-in modem, you need to decide where will you use it. If the device will be used in an office, then you need to buy it with an external antenna. It is installed outdoors to ensure better communication quality. If you need network connectivity on the go, 3G models are your best bet. Such devices easily fit into your pocket, and at the same time make it possible to access the Internet from several devices at the same time.

Since we're talking about a mobile router, let's talk about it. This device appeared not so long ago, but has already become popular among Internet users. These models decode the network signal and turn it into a radio signal. With this device you can use wireless network to access the Internet.

You can connect to the device directly, but this is not necessary. Mobile option provides a network for up to 10 gadgets via a wi-fi network.

The device can be purchased from several providers. Mobile router is compact. That is why it is convenient to take it on a trip or to study.

If you need to connect a modem to a router, then you need to do the following actions by setting. They are suitable for different models, from different providers:

Now you need to go to the router settings:

Now all you have left is to restart a computer. After which you will have access to the network via a modem, and you can also use the wi-fi network.

So, we have looked at the functions of the devices and their differences. There is a difference between them. The router can distribute Wi-Fi, which allows multiple devices to connect to the network. As for 3G models, they connect directly to the computer and allow only it to access the Internet. Now providers offer the use of a two-in-one device. That is, a router with a built-in modem. You can buy it in an online store or in a regular store. Whether you need such a device at home is up to you to decide.

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 company AT and T. 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 telephone system. 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 internet via 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 operate over the telephone network. Their speed reaches only 56 kilobits per second. Analog gadgets have been replaced by ADSL technology and now it is 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 necessary for him 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.

Principle of operation

This device (regardless of USB or landline) 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.