What are modems? Operating principle. Types of modems

When you first connect a laptop or a personal computer to the Internet from poorly versed users, the question usually arises: "What are modems and why are they needed?" This article will classify the modems, as well as an algorithm for their installation and configuration, Which, without much difficulty, a beginner computer specialist will be able to choose and make such a device work.

What it is?

First, let's look at what modems are. This is a special component in the computer that is designed to connect it to the computer network. The word "modem" was formed by combining two terms. The first of these is the modulator. So in electronics is called a special circuit, which encodes the signal. And the second is a demodulator. That is, the device that makes the action, the inverse of the modulator. One of them encodes and transmits the signal, and the second receives and converts. So, until recently, most of the personal computers were connected to the Internet using telephone wires. Now the situation has changed, and they are gradually being pushed out of this segment of the market by network cards. They have higher speeds, and most of them are equipped with them. But still there are wireless modems that do not yet have a real alternative.

When are you needed?

Now we will understand with what cases they are needed. In essence, there can be three such moments. The first of them is now slowly disappearing into the past. It consists in the fact that a personal computer with this device and telephone line connects to the Internet. Now it is being replaced by network cards. And the cost is lower, and the speed is several times higher. And the reliability of the connection in this case is an order of magnitude better. But for the "Client-Bank" system such a device is absolutely necessary (the second case). With the help of it, the accountant connects to the server of the financial institution. Without leaving the office, he can make a money transfer or check the availability of funds on the account. High speed in this case is not necessary. But the connection protection is needed at the proper level. Now many organizations in this format work with banks. The last case, when modems are in demand, if a person travels a lot. He needs a wireless internet connection. In this case, the question: "What are modems, and why are they needed?" - arises by itself. With the help of other technical means, this issue simply can not be solved.

By the way of execution

According to the method of execution, these devices are divided into two types: internal (that is, they are installed inside the computer's system unit) and external devices (for expansion of a computer, a laptop or a tablet). For the latter, you need to install a hardware toggle switch (if any) in the appropriate position. In this case, the following question should necessarily arise: "What is the modem mode?" They are digital or analogue - it is determined by the telephone line signal. For wireless modems only the first one is available. All cellular networks work only in this standard. Therefore, for wireless devices such a switch is not provided. One more point should be noted. On older motherboards there were integrated (ie soldered) similar devices. But now they are no longer found on new personal computers.

By connection

The second classification, which has been widely used to date, is based on the method of connection. In accordance with it these devices are divided into wired and wireless. In the first case, a special connector is provided in which the telephone wire is installed. In old devices, you could either talk on the phone or work on the Internet. Now there is a special modification of such devices. It allows you to simultaneously sit on the Internet and communicate on the phone. This is an ADSL modem. What it is? A special converter that separates the conversation and the transmitted signal into different frequencies. As a result, two data streams are transmitted over the same cable. In the second case, data transmission is provided by electromagnetic radiation without wires.

By type of supported networks

This option only classifies wireless devices. According to it, they are of the following types: GSM (they are also sometimes called 2G), 3G and LTE (another name is 4G). All of them are backward compatible. That is, 3G can easily work in a GSM network. Also, users are puzzled by what a USB modem is. It is in this form-factor that most of these adaptations are made. In appearance, it is a flash drive that provides wireless data transfer. Without fail, it is equipped with a SIM card slot. It is connected to a rectangular USB connector on a personal computer.

Manufacturers

Conditionally manufacturers of such equipment can be divided into two classes. The first of these is inexpensive and little-known trademarks, which include Sierra (their price starts from 180 rubles) and Sprint (the cost of such devices is 120-150 rubles). But the second class is more popular and high-quality devices. They are sold under the brands Pantech and Huawei. The price for them is already 600 rubles or more. But this is true for wireless devices. This often raises the question of what a 3G modem is. This is a miniature device (very similar to a flash drive externally), into which the SIM card of the mobile operator is installed, and with it the data exchange with the Internet is provided. In turn, among the wired devices the leading positions are occupied by "D-Link" and "A-Corp." It is recommended to pay attention to them when buying such a device. The price for some models of this segment starts from 120 rubles. At the same time, their quality is impeccable.

Customize

Consider the procedure for setting up an Internet modem. What is an Internet modem? This is all, without exception, devices of this class: both wired and wireless. So, the order of adjustment:

• Connection. For external - is to install them in the expansion slot of the computing device. But when installing an internal device, you need to remove the side covers of the PC system unit, install the card in the expansion slot, fix it and collect everything back.
• Installing the drivers. In most cases, it passes automatically, and the user's participation in this process is minimized. At the end, you should receive a message indicating the successful installation of this software. (If this does not happen, then they must be installed manually from the CD-ROM or from the Internet site.)
• Next we connect to the Internet.
• At the final stage, we launch the browser and check that the connection is working.

In some cases, you need to adjust the settings of the device (for example, change the analog dialing method to digital). This information is clarified by the provider and the telephone operator.

Summary

In this article, an answer was given to the question of what modems are and why they are needed. Possible performance of such devices is given. Their modes of operation and other technical characteristics are indicated. A tuning algorithm is also provided, following which it is possible to easily and easily configure such a device for connection to the computer network.