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

ADSL is an unbalanced Internet access technology. It is an asymmetric system by its structure and allows working with connections at speeds up to 8 Mbps. ADSL technology, the transmission rate of which is calculated up to 1 Mbit / s, operates on average over 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: "What is ADSL?", We offer you some historical data. For the first time, they started talking about the creation in the late 80s, when even the Internet in its modern guise was only its main task in 1989 was to improve and modernize the technology for transmitting data 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 LANs 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 via telephone channels. But telephone lines use an analog signal to carry voice messages. An ADSL connection is designed to convert an analog signal to digital and send it directly to a computer. At the same time, unlike the outdated Dial-up modems, devices based on ADSL do not block the telephone line and allow the use of digital and analog signals at the same time.

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

The most important advantage of ADSL technology is its budget and cost effectiveness. The fact is that the same copper ones are used to operate 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 needed. ADSL connects quickly, and modern types of modems are intuitive to operate 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, type of connection:

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

Additional equipment: splitters and microfilters

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

The main task of the splitter is the separation of frequencies - voice (0.3-3.4 kHz) and 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 phone 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 lightweight.

ADSL - what is it? High-speed Internet connection stages

Choosing a provider. Each provider offers to use this technology at the moment. Different types and rates 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. Nowadays, it is not at all necessary to buy a modem, splitters and microfilters. When signing 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 ADSL Internet - What Is It? It is a fast, cheap and high quality connection method.
Account activation. The provider reserves an account for each client, which can take up to 12 days to activate. However, in most cases, with normal network coverage, the procedure does not take more than a few hours. The provider first checks the phone number for ADSL connectivity. If the technology access zone is not enough, then high-speed Internet will not work.
Equipment setup. At this stage, the devices are connected to the telephone line, the splitters and microfilters are installed, the modem drivers are installed on the computer, and the modem's network parameters are set in the Internet browser.

pros

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

High ADSL allows you to easily transfer files of any size without long waiting times. 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, there is no need to lay a cable to the subscriber and install a large amount of equipment. The reliability, quality and functionality of the network are improved.
No interference on the telephone line. The ADSL router operates in an independent mode and does not create any problems for the phone. You can make calls and travel around the virtual space completely free.
Constant ADSL Internet access. 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 all the time and can be online around the clock.
Reliability and stability. ADSL is the most reliable type of Internet connection today.
Profitability. The cost of connecting ADSL and installing a modem with a router is minimal and will not hit the family budget.

disadvantages

No cross talk protection. If several dozen clients are connected to one channel, you will not have to rely on high speed. The more subscribers on one ADSL, the lower the quality of data transmission.
Although ADSL technology has some drawbacks, they are few and far between. This can also include the minimum speed from the subscriber. The asymmetry of ADSL has an obvious disadvantage - the file transfer from the subscriber will be long and inconvenient. But the technology is intended primarily 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 \u200b\u200band factors affecting it

ADSL is a high-speed Internet technology, but there is no universal meaning and 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 slow speed of ADSL connections is the quality of the subscriber line. We are talking about the presence of cable branches, their condition, wire diameter and length. Signal attenuation is a direct consequence of increasing the length of the subscriber line, and interference can be reduced by expanding the wire diameter. The standard length of an ADSL channel does not exceed 5 km - the optimal range for high-speed data transmission.

Speed \u200b\u200bcharacteristics

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

ADSL technology, the maximum speed of which is also determined by the characteristics of the modem and can reach 2048 Mbit / s, optimizes the information transfer process. Digital lines significantly increase the user's experience, pushing him beyond the limits even with several connected computers, mobile phones, tablets and other gadgets.

Technology Perspective

The capabilities and resources of ADSL technology are far from being exhausted. Even the ADSL2 and ADSL2 + standards, introduced in the mid-2000s, still retain their relevance and capabilities. It is, in fact, the only technology that can provide broad Internet access without glitches and software problems, and therefore competes with many other methods of connecting to the Internet.

The minimum technical equipment is complemented by modern types of modems. Manufacturers annually release new devices designed for continuous operation without the need for maintenance and service. Moreover, ADSL speed is constantly increasing and is not limited to megabits. Connection becomes relevant both for home and for an entire office company with several dozen computer clients.

Conclusion

So, we found out what ADSL technology is, what is its essence and how it works. 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, she does not need constant reconnections and speed limits.

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

"The last mile" - a channel connecting the end (client) equipment with the access node of the provider (telecom operator).

In this embodiment, the last mile is a two-wire copper wire. From the provider's side, this is the PBX, from the client's side, this is his xDSL modem.

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

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

Telephone line parameters.

First of all, of course, for good work without breaking the connection, you need a high-quality data line. The telephone line has primary parameters and secondary parameters.

Line primary parameters:

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

If one of these parameters is understated beyond the normal range, or even several, it will have a critical effect on 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 only available 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 - malfunctions are possible;
from 11 dB to 20 dB - a good line, no problems with synchronization;
20 dB to 28 dB is a very good line;
from 29 dB is an excellent line.

Attenuation [dB]:

up to 20 dB is an 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 more - the equipment will not work.

Upstream / Downstream DataRate - data transfer rate.

These parameters can be viewed by going into the settings of the router. How to enter the settings, see here.

Compare your connection settings with the information above if you are experiencing speed issues or connection drops.

Views count: 1 121

What is ADSL?

Asymmetric Digital Subscriber Line is a technology that allows realizing 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 - transmission is organized at a higher frequency than that of an analog telephone signal. Result: you have threads independent of each other and can conduct conversations while simultaneously being online. ADSL is currently capable of providing upstream data rates up to 24 Mbps and outgoing data rates up to 1 Mbps, but this is under ideal conditions, a short 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 Mbit / s.

In the case of ADSL, you simply connect to a telephone socket through a special device that separates frequencies — this is a splitter, a modem and a telephone are connected to it, and the device receives output directly to your telephone line.

Which modem should you choose?

Currently, ADSL modems with Ethernet and USB interfaces are available, and a wireless device - with Wi-Fi interface. The choice depends on your needs - the difference here is in the features of the connection and in the possibilities provided: modems that connect as network devices offer more of them than their USB counterparts. For example, in order 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 have an Ethernet or Wi-Fi interface in any case.

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 multiple computers). If you need increased security, you can look at models with Firewall functions, anti-virus scanning, the ability to work with a virtual private network and other "usefulness".

In case of using on the same line, in addition to telephony and Internet DSL, also signaling, then you will need a modem that supports the ANNEX B operating 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 parallel-connected telephones 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 headache, which is 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 side of the splitter has two inputs (Phone and DSL), a telephone cord from a modem is connected to the DSL input, and a telephone set to Phone. The splitter is a frequency splitter, or, as it is easier to say - it allows you to surf the Internet and communicate 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 blink. The main indicator is the DSL light, which should be on without blinking after the modem is restarted. If the light is on properly, you can connect the modem to a laptop or computer using an Ethernet RJ45 network cable. It so happens that the light blinks quickly or just does not light up. You can solve the problem by checking the quality of the cable connections and wiring diagram or by calling the provider. Move on. The lights are on as needed. When you turn on the computer, connect the modem to the output of the network card, which is slightly wider than the telephone one.

When creating a new internet connection, you just need to set up your modem.
Depending on the configuration of your local network, the modem can be configured in the so-called bridge mode.
Choosing an ADSL modem and setting it up is a very simple task if an agreement was 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 from English stands for Asymmetric Digital Subscriber Line. There are several types of DSL connections: ADSL, HDSL, and VDSL. At the heart of 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 with every citizen of the country. In the late 80s - early 90s, the first version of the ADSL protocol appeared. She supported incoming traffic speed up to 1 Mbit / s, and outgoing - up to 8 Mbit / s.

ADSL originated from Bellcore, which in the mid-eighties was looking for methods to create interactive TV. Further, the technology was adopted by the providers of access to the "world wide web". Thus, the first devices that transmit and receive signals appeared - ADSL modems.

An asymmetrical line today used in remote settlementswhere it is impossible 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 one. Earlier we mentioned the approximate figures - the difference in speed can reach eight times.

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 wire 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.

Equipment used

As with any technology, ADSL also uses special equipment and components. Let's consider in more detail using the example of the diagram below.

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

ADSL modem

The network device is the entry point for the analog data stream. He can convert signal in both directions simultaneously, which allows for more efficient use of bandwidth.

Pure ADSL modems are almost not produced any more, 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 veins, through which the analog signal is transmitted to the input and output.

Routers

Improved version of the modem. It is equipment 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 that allows mobile devices to connect to the Internet.

Splitters and microfilters

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

The principle of operation is as follows. One incoming signal - several outgoing ones. The simplest example of a splitter is shown in the screenshot above. It can split into a maximum of 16 signals.

Microfilters are needed to create two parallel signals. This allows you to use ADSL Internet and phone at the same time, without interfering with the line.

Other equipment

There are other devices used to create a connection to the World Wide Web based on ADSL technology.

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

The second common option. There is an office space where access to the global network is organized using ADSL technology. To provide the Internet in each room, you must purchase switches and router... The first ones are installed in each office separately, and the router will carry out the correct routing of data within the local network.

The main stages of connection

The first thing to do is to connect the telephone cable that goes into the room through the splitter. Further 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 network and connect it to the workstation via an Ethernet cable.

At the last stage, the user spends setting up network equipment according to 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. the specified values \u200b\u200bare achieved under ideal conditions... In fact, 13-15% of the speed is lost when the signal passes from the provider to the endpoint. This fact is due to the technical characteristics of the equipment used.

Also, do not forget about other subscribers. The signal comes from a single point of exit from 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

Advantages of using ADSL technology:

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

Disadvantages:

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

It might be helpful to read: