Adsl connection what. See what "ADSL" is in other dictionaries. Advantages and features of using ADSL technology

ADSL is an asymmetric Internet access technology. It is an asymmetric system in its structure and allows you to work with connections at speeds up to 8 Mbps. ADSL-technology, the transmission speed of which is calculated up to 1 Mbps, operates on average at a distance of more than 5 km. Today we will look at what this type of connection is and how it works.

History of appearance

Before answering the question: "ADSL - what is it?", we bring to your attention some historical data. For the first time, they started talking about creation in the late 80s, when even the Internet in its modern form was only its main task in 1989 was to improve and modernize the technology of data transmission over copper telephone wires. Analog-to-digital conversion was created mainly for the rapid transfer of information between various interactive services, video games, video files, as well as for instant remote access to LAN and other network systems.

Modern ADSL technology: how it works

The operation of the network is based on the subscriber's digital line, which provides access to the Internet through telephone communication channels. But telephone lines use an analog signal to carry voice messages. An ADSL connection is designed to convert an analog signal into a digital one and transfer it directly to a computer. At the same time, unlike already outdated Dial-up modems, ADSL-based devices do not block the telephone line and allow you to use digital and analog signals simultaneously.

The essence of the technology (asymmetry) lies in the fact that the subscriber receives a huge amount of data - incoming traffic, and transmits a minimum of information from himself - downstream traffic. As an input, various kinds of content are meant: video and media files, applications, objects. Downstream sends only important technical information - various commands and requests, emails and other secondary elements. The asymmetry is that the speed from the network to the subscriber is several times higher than the speed from the user.

The most important advantage that ADSL technology has is its budget and economy. The fact is that the same copper ones are used for the operation of the system. The number in them, of course, significantly exceeds the number of similar elements in cable modems. But at the same time, no modernization of switching equipment and complex reconstruction is necessary. ADSL connects quickly, and modern types of modems are intuitive to manage and configure.

What equipment is used for this connection?

In order for the technology to work, special types of modems are used, which differ in their structure, design, connection type:

PCI modems (internal computer devices).
External modems with USB connection type.
Devices with Ethernet type interface.
with Ethernet scheme.
Profile types of modems (for security companies, private telephone lines).
Router with internal Wi-Fi hotspots.

Additional equipment: splitters and microfilters

We must not forget that to connect such a gadget as an ADSL modem, you will need splitters and microfilters. Devices are selected in accordance with the design of the telephone cable. In a situation where a cable outlet is made (or can be done) to separate the modem and telephone channel, a splitter is used. In another case, the purchase of a microfilter is required, which is installed on each telephone present in the room.

The main task of the splitter is to separate frequencies - voice (0.3-3.4 kHz) and those used directly by the modem itself (25 kHz-1.5 MHz). It is in this way that the simultaneous operation of the modem and the telephone is ensured, which do not interfere with each other and do not interfere. Splitters are compact and will not cause unnecessary inconvenience. The miniature box is equipped with three connectors and is light in weight.

ADSL - what is it? Stages of connecting high-speed Internet

Provider choice. Use this technology currently offered by every provider. Different kinds and tariffs depend on the region, as well as on the technical capabilities of the company, the coverage area of \u200b\u200bwhich may be limited.
Purchase of equipment. Currently, it is not necessary to buy a modem, splitters and microfilters. When drawing up a connection agreement, the provider offers to rent the necessary equipment, including an ADSL modem. In the future, upon termination of the document, the equipment is returned back. The client pays exclusively for the Internet connection. Modern Internet ADSL - what is it? This is a fast, cheap and high-quality connection method.
Account activation. For each client, the provider reserves an account, the activation of which can take up to 12 days. However, in most cases when normal coverage network procedure does not require more than a few hours. First, the provider checks the phone number for the possibility of connecting ADSL. If the technology access zone is not enough, then high-speed Internet will not work.
Equipment setup. On the this stage devices are connected to a telephone line, splitters and microfilters are installed, modem drivers are installed on a computer, and modem network parameters are set in an Internet browser.

pros

What are the advantages of ADSL technology? Here are a few of them:

High ADSL allows without special work transfer files of any size without a long wait. The technology is constantly being improved, and the speeds are growing, significantly expanding the capabilities of the subscriber.
Wireless connection. To use an ADSL system, you do not need to stretch the cable to the subscriber and install a large amount of equipment. The reliability, quality and functionality of the network is improved.
No interference on the telephone line. The ADSL router operates in independent mode and does not create any problems for the phone to work. You can call and surf the virtual space completely freely.
Permanent Internet access ADSL. What it is? This means that the network will not fail during operation. The technology does not require reconnection. The user gets access to the Internet constantly and can be online around the clock.
Reliability and stability. Today, ADSL is the most reliable type of Internet connection.
Profitability. The cost of connecting ADSL and installing a modem with a router is minimal and will not hit the family budget.

disadvantages

Lack of crosstalk protection. If several dozen clients are connected to one channel, count on high speed won't have to. The more subscribers on one ADSL, the lower the quality of data transmission.
Although ADSL technology has disadvantages, they are not numerous. This also includes the minimum speed from the subscriber. The asymmetry of ADSL has an obvious minus - the transfer of files from the subscriber will be long and inconvenient. But the technology is intended, first of all, for quick access to the Internet, for surfing. In addition, the information transmitted from the subscriber takes up a minimum of space and does not require a large resource.

Speed and factors affecting it

ADSL is a high-speed Internet technology, but there is no universal meaning or formula. For each individual subscriber, the speed is individual and is determined by a whole set of factors. Including some of them can affect the reliability and quality of equipment. Therefore, it is best for professionals to install modems and routers.

The main reason for the low speed of an ADSL connection is the quality of the subscriber line. We are talking about the presence of cable outlets, their condition, the diameter of the wires and the length. Signal attenuation is a direct consequence of an increase in the length of the subscriber line, and interference can be reduced by expanding the diameter of the wire. The standard length of an ADSL channel does not exceed 5 km - the optimal range for high-speed data transmission.

Speed characteristics

Compared to other Internet connection technologies, ADSL has a significant speed advantage. An analog modem will give a maximum of up to 56 Kbps, while ADSL at the dawn of its appearance already allowed information to be transmitted at speeds up to 144 Kbps.

ADSL technology, maximum speed which is also determined by the characteristics of the modem and can reach 2048 Mbps, optimizes the process of information transfer. Digital lines greatly increase the user's capabilities, taking him beyond the limits even if there are several connected computers, mobile phones, tablets and other gadgets.

Technology Perspectives

The possibilities and resources of ADSL technology are far from being exhausted. Even the ADSL2 and ADSL2+ standards, introduced back in the mid-2000s, still retain their relevance and capabilities. This is, in fact, the only technology that can provide wide Internet access without failures and software problems, therefore it is a competitor to many other methods of connecting to the Internet.

Minimum technical equipment complemented modern views modems. Manufacturers annually release new devices designed for continuous operation without the need for maintenance and service. In addition, ADSL speed is constantly growing and is not limited to megabits. The connection becomes relevant both for the home and for the whole office company with several dozen computer clients.

Conclusion

So, we found out what ADSL technology is, what is its essence and principle of operation. As you can see, this is one of those technologies that practically does not fail during operation (even if several dozen users are connected to the network). At the same time, it does not require constant reconnections and speed limits.

ADSL(English) Asymmetric Digital Subscriber Line - asymmetric digital subscriber line) - a modem technology in which the available channel bandwidth is distributed asymmetrically between outgoing and incoming traffic. Since for most users the volume of incoming traffic significantly exceeds the volume of outgoing traffic, the speed of outgoing traffic is much lower.

In order to provide a large coverage of their users with an Internet channel, providers often use this technology for their last mile, due to the low cost of its implementation and a fairly high data transfer rate.

"Last Mile"- a channel connecting the end (client) equipment with the provider's (communications operator's) access node.

In this variant last mile This is a copper wire. From the provider's side, this is a PBX; from the client's side, this is his xDSL modem.

This technology gained immense popularity during the dawn of high-speed internet. But it is worth mentioning that ADSL did not appear immediately in the form in which we are now observing it. there was still dial-up before it, then dsl developed in terms of data transfer speed.

At the moment, ADSL + technology supports speeds up to 24Mb / s. (Well, this is of course in the most ideal conditions)

Phone line settings.

First of all, of course, for good work without interruptions in the connection, a high-quality data transmission line is required. A telephone line has primary parameters and secondary parameters.

Primary line parameters:

Loop resistance - no more than 1000 Ohm
Insulation resistance - not less than 40 MOhm
Loop capacitance - no more than 300 nF
Capacitive asymmetry - no more than 10 nF, or no more than 5%

If one of these parameters is underestimated beyond the norm, or even several, it will critically affect the speed and stability of the connection. Usually, these parameters can be used to determine the nature of the line damage. But this information is available only to the provider.

Secondary line parameters:

signal Noise Margin (SNR)[dB]:

up to 6 dB - bad line, there are synchronization problems;
from 7 dB to 10 dB - failures are possible;
from 11 dB to 20 dB - a good line, no problems with synchronization;
from 20 dB to 28 dB - a very good line;
from 29 dB - excellent line.

Attenuation[dB]:

up to 20 dB - excellent line;
from 20 dB to 40 dB - working line;
from 40 dB to 50 dB - failures are possible;
from 50 dB to 60 dB - synchronization periodically disappears;
from 60 dB and above - the equipment will not work.

Upstream/Downstream Data Rate— data transfer rate.

These parameters can be viewed by going to the router settings. See here for how to access settings.

Compare your connection settings with the information above if you're experiencing speed issues or dropouts.

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What is ADSL?

Asymmetric Digital Subscriber Line is a technology that allows you to implement high-speed data transmission over a telephone line (ordinary copper telephone wire).

At the same time, there are significant differences from voice-frequency telephone modems - the transmission is organized at a higher frequency than that of an analog telephone signal. The result: you have threads that are independent of each other and can carry on conversations while being on the Web in parallel. ADSL is currently capable of providing up to 24 Mbps of downstream data and up to 1 Mbps of outgoing data, but this is under ideal conditions, a small distance from the station and underground cable laying, etc. For the most part, the connection speed depends on the technical capabilities of the provider and on average reaches 6-8 Mbps.

In the case of ADSL, you simply connect to a telephone jack through a special device that performs frequency separation - this is a splitter, a modem and telephone are connected to it, and the device gets output directly to your telephone line.

Which modem to choose?

Currently available are ADSL modems with Ethernet and USB interfaces, and a wireless device with Wi-Fi interface. The choice depends on your needs - the difference here is in the connection features and in the capabilities provided: modems that connect as network devices offer more of them than USB counterparts. For example, to connect one computer to the Network, a simple model is quite enough, and if there are two or more of them, then you need to pay attention to devices with a router function - the modem will in any case have an Ethernet or Wi-Fi interface.

You can find options from Ethernet models with and without a built-in switch (in this case, you will need to use an additional switch when connecting several computers). If you need increased security, then you can look at models with Firewall functions, anti-virus scanning, the ability to work with a virtual private network and other “usefulness”.

If you use signaling on the same line, in addition to telephony and Internet DSL, you will need a modem that supports ANNEX B operation mode, it can be either a separate modem model or a built-in switching capability (ANNEX A - ANNEX B).

How to connect?

An important detail: if there are phones connected in parallel in the apartment, and you cannot connect them through a splitter (they are located in other rooms), then each incoming call will cause a lot of headaches, which are associated with constant disconnections. To avoid this, it is necessary for each of the devices to buy an additional device, a microfilter, and connect them through it. One of the sides of the splitter has two inputs (Phone and DSL), a telephone cord from the modem is connected to the DSL input, and a telephone set is connected to the Phone. A splitter is a frequency separator, or, to put it simply, it allows you to surf the Internet and talk on the phone without any interference.

Now we need to turn on the modem itself and look at it. The lights should come on and flash. The main indicator is the DSL light, which should be on without blinking after the modem is restarted. If the light is on correctly, then you can connect the modem to a laptop or computer using an Ethernet RJ45 network cable. It happens that the light flashes quickly or simply does not light up. You can solve the problem by checking the quality of the cable connection and the connection diagram or by calling the provider. Move on. The lights are on as they should. When you turn on the computer, connect the modem to the output of the network board, which is slightly wider than the telephone.

When you create a new Internet connection, you just need to set up your modem.
Depending on your configuration local network the modem can be configured in the so-called bridge mode (bridge).
Choosing an ADSL modem and setting it up is a very simple task if an agreement has been concluded with a provider from which you received a login and password, as well as a notification that the line was connected to the Internet.

ADSL with in English stands for Asymmetric Digital Subscriber Line. There are several types of DSL connections: ADSL, HDSL, and VDSL. Based on all three options there is a telephone line.

What is ADSL

DSL technology was developed at a time when the telephone line became popular and appeared in every citizen of the country. In the late 80s and early 90s, the first version of the ADSL protocol appeared. She supported incoming traffic speed up to 1 Mbps, and outgoing - up to 8 Mbps.

ADSL was born thanks to Bellcore, which in the mid-eighties was looking for methods to create interactive TV. Further, the technology was adopted by service providers of access to the World Wide Web. Thus, the first devices that transmit and receive signals appeared - ADSL modems.

Asymmetrical line today used in outlying areas where it is not possible to use other wired technology or wireless communication via 3/4G USB modems

ADSL technology - how it works

The first word in the name - asymmetric - implies that it is used uneven distribution telephone line between receiving and sending data.

In this case, the incoming traffic has a higher bandwidth than the outgoing traffic. Earlier we mentioned approximate figures - the difference in speed can be up to eight times the value.

The use of a telephone line as a means of data transmission implies that ADSL uses another frequency in cables. This fact allows you to use the phone and the Internet at the same time, without interfering with each other.

Sometimes there are situations in which the use of a telephone core for two directions leads to certain interference, but such cases are rare and are associated with improper cable shielding.

The signal comes from the provider and comes to the end user on special equipment - a modem. It translates the incoming data stream into a digital value.

Used equipment

As with any technology, ADSL also uses special equipment and components. Let's take a closer look at the example circuit below.

The signal coming from the telephone socket is initially sent to a special device - splitter. He divides it into telephone and high frequency. The first goes directly to the communication device, and the second to the translator. In turn, the network device processes the incoming analog stream into a digital one. After this operation, the data can be processed operating system end user device: for example, a workstation or tablet.

ADSL modem

The network device is the entry point of the analog data stream. He can convert signal in both directions at the same time, which allows you to use the bandwidth more efficiently.

Pure ADSL modems are almost no longer produced, as there is more modern network equipment - routers. They will be discussed below.

ADSL cable

The cable is a wire with an RJ-12 connector. It is used to connect a telephone line to a modem.

Contains four cores, through which an analog signal is transmitted to the input and output.

Routers

Improved modem. It is a device capable of not only receive and transmit signal to the end user, but also route traffic within the local network.

Using an ADSL router, a user can connect multiple devices to gain access to the World Wide Web.

Today, most ADSL routers have a built-in WiFi module, which allows you to connect mobile devices to the Internet.

Splitters and microfilters

To separate the signal coming through the telephone line for the modem and telephone, a special filter is used - a splitter.

The principle of operation is the following. One incoming signal - several outgoing. The simplest example splitter is shown in the screenshot above. It can split up to 16 signals at most.

Microfilters needed to create two parallel signals. This allows you to use ADSL Internet and phone at the same time, without creating interference in the line.

Other equipment

There are other devices that are used to create a connection to the "world wide web" based on ADSL technology.

For example, a user has only an ADSL modem but wants to use wireless at home. He will have to purchase additional router withWi— fimodule. It connects via an Ethernet port to a modem.

The second common option. There is an office space where access to the global network is organized through ADSL technology. To provide Internet in each room you need to purchase switches and router. The first ones are installed separately in each office, and the router will correctly route data within the local network.

Basic connection steps

First of all, we connect the telephone cable going into the room through a splitter. Coming from connector Phone we bring the wire to the phone, and from ADSL– to network equipment.

The next step is to connect the ADSL device to the power supply and connect it to workstation via an Ethernet cable.

In the last step, the user setting up network equipment in accordance with the instructions provided by the provider.

Maximum ADSL Speed

The data transfer rate when using ADSL depends on the standard used by the provider. The last option is ADSL2++. The data can be summarized in one table.

The information presented above is theoretical, i.e. specified values are achieved under ideal conditions. In fact, 13-15% of the speed is lost when the signal passes from the provider to the end point. This fact is due technical specifications equipment used.

Also, do not forget about other subscribers. The signal comes from a single point of exit of the service provider. Many other clients are connected to it, respectively, the total speed value begins to be divided into equal parts.

Advantages and disadvantages of technology

Benefits of using ADSL technology:

Subscribers receive high frequency access service to the "world wide web" without laying additional cables in the room.
Organize global network can be used almost anywhere where there is a telephone line.
Initial financial expenses on connection below some other methods.
high download speed files for the end client.
Using modern network equipment, the client can set up a wireless network.

Disadvantages:

Exists more modern solutions Internet connections that provide high download speeds.
Technology gives away most of the channel for incoming traffic, and the outgoing one is several times lower. Accordingly, sending larger files to another subscriber will take a long time.
Signal quality and stability depends on telephone line which is not designed for high frequency signals.

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