adsl connection technology. Internet connection speeds. Pros and cons of XDSL connection

Hello Irina!

Basically, you can watch movies online at any speed.

Another question is how much it will cost nerves and health at very low speeds.

I will give an example specifically for your reception speed in numbers. Do not delve into the numbers, the main thing is the meaning.

Judging by the designation 1.55 M b/s, you have a speed of 1.55 Megabyte per second. The capital letter "M" indicates this.

Movies online, depending on the format (in my "Additional Materials" there is a link to my lesson on this topic, on films, in particular) and quality, the size of an average-quality online movie can be from 300 megabytes to 5000 megabytes.

Let's take something in the middle, for example, the size of a movie is 1000 megabytes.

How is watching a movie online?

When you enter the page for watching a movie, a player appears on your screen for viewing with the buttons "Pause", "Playback", "Stop".

When you click "Play", the movie starts downloading to your computer.

As soon as a very small part of the movie, which the player is already capable of playing, is downloaded to your computer, the player (after a few seconds) starts showing you the movie.

And the rest of the movie continues to swing in the background.

It turns out that the whole movie has not yet been downloaded, and you are already watching it.

So the problem with low reception speeds is that while you are viewing the first downloaded part, the next one does not have time to download to your computer. Then the Brakes begin. What hits the nerves.

But in this case, there is a way out. The truth takes some time. You put the player on "Pause" and do other things. After 5-10 minutes, turn on playback and watch the movie normally.

Now for your speeds.

Roughly speaking, a 1000 megabyte movie should be downloaded for

1000Mb / 1.55Mb/s = 645 seconds = 10 minutes

Judging by my observations, this is a fairly comfortable viewing of an average quality movie.

Now a little fly in the ointment.

The reception speed of 1.55 Mb/s does not mean at all that the movie will be downloaded at that speed.

1. In addition useful information(of the film itself) there is a lot of service information in the communication channel.

2. A lot depends on the workload of the site from which you are watching the movie.

3. Much depends on the workload of the channels through which you receive information.

4. A lot depends on how loaded your computer is directly - how many programs and processes are loaded and how much they “eat away” the memory and resources of the processor itself.

5. What is the quality of the movie you are watching - low, medium or high.

In general, we make discounts for factors on which we do not depend and it turns out (according to experience) somewhere around 20 - 40 minutes.

But, that's also acceptable. After all, the player has a "Pause" button.

And finally. The whole movie, in fact, is not downloaded to the computer. Parts only. Viewed parts are automatically deleted.

Regards, Oleg

One of the most popular and affordable ways to connect to the World Wide Web today is an ADSL connection. The abbreviation ADSL stands for "Asymmetric Digital Subscriber Line" - an asymmetric digital subscriber line. Despite the simplicity and almost one hundred percent availability, mobile connection significantly loses in its capabilities to an ADSL connection: the data transfer rate is lower, the range of services is smaller, and the connection cost is much higher. Connection using ETTH technology (“Ethernet to every home”), GPON and FTTH (using fiber optic cable) is currently available only for residents of the multi-apartment sector in large settlements, as they are economically justified for mass connections. Therefore, today ADSL connection is relevant for most users, especially in small towns.

ADSL connection problems

Despite its mass availability and fairly decent technical characteristics:

1. Practical access speed: up to 24 Mbps;
2. Subscriber line length for satisfactory operation: up to 7.5 km;
3. Service availability triple play- simultaneous transmission of voice, video and data.

This technology uses in its work a telephone subscriber line with all the ensuing problems.

Consider a typical subscriber connection scheme using ADSL technology:

The practice of operating this technology shows that the most common problems that lead to the fact that the user installs slow speed on adsl connection, or no Internet access at all, are:

1. Malfunction telephone line;
2. Access equipment port failure (DSLAM) on the provider side;
3. Incorrect connection on the user's side.

Telephone line failure

This is the most common type of damage that occurs in the "Subscriber-Provider" chain. Unfortunately, the telephone line is far from perfect. While it "gets" from the Internet provider to the user, it can go through quite a lot of different sections: trunk, cable, distribution cables, cables between cabinets and even the so-called air ducts - wires that go from the cabinet to the subscriber by air. Each of these sections, in addition to attenuation of the useful signal, can also introduce various interferences, leading both to a general decrease in speed and to the fact that the subscriber has frequent disconnections during adsl connection.

Of course, in order to perform a measurement of the physical parameters of a telephone line to obtain it quality characteristics, requires the availability of special tools and the ability to use them. But an ordinary user can also easily assess its condition in order to understand why certain access problems arise. To do this, you need to connect to an ADSL modem and view the ADSL connection statistics.

Not only problems with the communication line or with the provider's equipment lead to problems in working with the Internet. Asking the question - “How to increase the speed with an adsl connection?”, The user sometimes forgets that incorrectly working equipment or an incorrect connection on his side can also cause failures and low speed. Therefore, before calling the service technical support, you need to check if the telephone line, modem and telephone are connected correctly.

First of all, you should start with splitter- a special device that is designed to ensure that high-frequency noise from the modem does not interfere with telephone conversations. In fact, it is a special filter for separating the operating frequency bands of the modem and the telephone.

Consider the correct scheme for connecting user devices:

It should be remembered that telephone sets and any other telephone devices must not be connected before the splitter! All phones must be strictly connected to the PHONE jack! Otherwise, the connection will be unstable, and usually slow. Adsl connection breaks will be almost permanent in this case.

Connecting an adsl modem without a splitter will cause noise during telephone conversation and, as in the first case, to the poor quality of the connection. However, if you are not using a telephone set, then the modem can be connected to a telephone line without this device.

Excessively long telephone extension cords should be avoided. If you really can’t do without it, you need to choose those that use not four, but two conductors. This will reduce the level of interference and improve the quality of the connection.

Unfortunately, the adsl modem is also not immune from damage. Moreover, there are obvious damages, that is, when it simply does not work or does not work correctly, but there are hidden ones associated with damage to its linear part. Especially often, such malfunctions quite often occur after a thunderstorm. At the same time, the modem itself is working and can even establish a connection with the provider's equipment, but it is unstable, or the connection is at low speed. The first impression that arises is that the telephone line is malfunctioning, since the “symptoms” are very similar. In this case, you should take readings of the main characteristics of the connection from its menu in the "Statistics" section, and check it at the provider's stand, asking you to take the same data. If the readings are similar, most likely, the linear part of the modem is “burned out” and needs to be repaired.

1. If the Internet access speed periodically decreases, start the test by examining the stability of the established connection - the "link". (The English version of the word is Link). Follow the indicator with the same name. On some models it is called ADSL. During operation, if the adsl connection is stable and established, it should just be on. If it blinks periodically, the connection with the provider is unstable, a check of the communication line is required.
2. Watch outgoing (upstream) speed in the line. Practice shows that the lower it is, the lower the quality of the connection. Ideally, it should be equal to or close to 1 Mbps (unless specifically limited by the tariff).
3. With constant disconnections, you can try to turn off the splitter and phone, turning on the modem for a while, directly into the line. This eliminates the possible influence of other devices on the connection. If in this case everything works stably, then you can, turning on the devices in turn, find out which one has an impact.
4. Always check the quality of the contact in the connectors. The modern RJ11 telephone jack is not a very high quality product, its contacts are often oxidized. Remove and reinsert it two or three times.

There are several ways to access the Internet using a regular telephone cable, and ADSL technology is one of them. The purpose of this article is to tell the reader what is an ADSL modem how data is exchanged, and what is the advantage of this method of organizing information transfer.

What is ADSL and how does it work

Digital Subscriber Line or DSL (Digital Subscriber Line) for short, is a way to organize data exchange by creating a high-speed connection for their transfer between two or more computers. To combine computers into a computing local network or to access the Internet, special DSL modems are used on the client side, and switches on the provider side.

The technology appeared in the late 80s of the last century and combines several technologies under the common name xDSL:

• ADSL stands for Unbalanced Digital Subscriber Line or Asymmetric DSL. The data transfer rate reaches 8 Mbps for receiving, and up to 1 Mbps for sending data from the subscriber;
• HDSL - high-speed digital subscriber line or High Data Rate DSL, where the transmission rate is up to 2 Mbps in two directions;
• VDSL - Super High Speed ​​Digital Subscriber Line or Very High Data Rate DSL when the highest speed of 52 Mbps is reached.

When used by private subscribers, the technology of asymmetric data transmission has become the most popular. This allows you to use one phone line for Internet access and for regular calls. High connection speed is achieved by using a higher frequency than that used by a conventional dial-up modem.

The principle of asynchronous data transfer is quite simple:

• Frequencies up to 4 kHz are used directly for telephone communication or for faxing.
• When creating a connection between the client modem and the provider's modem, frequencies from 4 to 140 kHz are used. At these frequencies, data is transmitted from the client to the Internet provider. Because relatively little data is sent from the client, there is no need to use higher frequencies, and, accordingly, higher speeds. The speed rarely exceeds 1 Mbps.
• Frequencies from 1.1 to 4.4 MHz are used for incoming traffic. The connection speed here reaches 8 Mbps.

What is an ADSL modem

When connecting to the Internet via an ADSL line, the user does not need to perform any additional actions, for example, make a call to the provider, as in a dial-up connection. All necessary work the modem will do it for the client. So, what is adsl modem? This is a high-tech device that is designed to convert an incoming or outgoing signal from analog to digital and vice versa. The modem creates a permanent broadband connection and monitor its stability.

Constantly improving ADSL technology has undergone several evolutionary transitions, which is reflected in the ADSL modems offered for purchase, which are now of the following types:

• internal modem for connection to the PCI slot;
• external version with USB or Ethernet connectors;
• external routers with Ethernet ports;
• outdoor routers with built-in WiFi access point.

Now that it's a little clearer how it works adsl modem what it is and about the technology in general, we can conclude about the advantages and disadvantages of using the described technology to access the Internet.

Advantages and disadvantages of an ADSL connection

The most obvious advantages of ADSL technology are very high data transfer rates and connection stability. But there are a few more important points that speak in favor of ADSL:

• permanent connection and access to the Internet;
• there is no need to lay additional cables, because the telephone line has already been laid in almost every apartment, office or house;
• using both the telephone and the Internet at the same time, on the same telephone line;
• relatively low price for equipment and provider services.

The disadvantages of this type of connection are mainly the low quality of telephone lines, which can significantly reduce the data transfer rate and a rather low speed for outgoing traffic. But the technology is developing and these problems should be solved in the near future.

What is ADSL? This is a technology that provides asymmetric access to the global network at high speed through a telephone line. The development of this high-speed connection began back in the eighties of the last century, in order to increase the maximum data transfer rate, using copper cable communication lines common at that time. ADSL technology was intended for high-speed data exchange between interactive services and providing high-speed remote access to various network systems.

How does the technology work?

The operation is based on providing access to the Internet with ADSL technology through telephone channels (asymmetric digital subscriber line). Due to the use of an analog signal type in telephone lines, it needs to be converted to digital, that is, an understandable signal for computer technology. At the same time, the technology allows, with constant access to the worldwide network from a computer, to leave the phone connected to the same line free. Thus, you can talk on the phone and have high-speed Internet access through your computer at the same time.

Achievement principle high speed ADSL-reception of data from the network lies in the asymmetry of the technology, since in this case the transmission rate outgoing from the subscriber is several times lower. It should also be noted that one of the main advantages of using to connect to world wide web ADSL modem is low cost. There is no costly new cabling required and existing telephone lines are used.

What is required to connect?

A mandatory requirement when using DSL modems is the connection of a special additional equipment such as microfilters or splitters. The type of equipment used mainly depends on the type of telephone line. If it is possible to tap the telephone line in order to separate the telephone and modem lines, then a splitter must be installed. When this is not possible, a microfilter is used. If several phones are used, then all must be equipped with their own microfilter.

How to connect?

At the first stage, the user must decide on the Internet provider company. Fortunately, all providers without exception are now successfully working with this technology, so the choice of a subscriber comes down to an analysis of the tariffs they offer, the area of ​​the company's work and additional offers from them. Most providers fully provide their client with all the required equipment, so the user only bears the cost of accessing the Internet. The client receives for rent suitable for specific conditions equipment for DSL, as well as the modem itself.

Next, the provider analyzes the client number for the absence of obstacles to the use of ADSL. Then, after signing the contract with the service provider and connecting necessary equipment, the account is activated. This process takes no more than two weeks. If the network coverage area is satisfactory, then only a couple of hours will be spent on the procedure.

On the final stage connection parameters are configured, installation of the necessary software on the user's PC or laptop.

Advantages

The main advantages include the following:

1. Big maximum speed data reception, which reaches 2000 Mbit / s;
2. Ability to use wireless routing;
3. Simultaneous use of the phone and the Internet channel around the clock;
4. No interruptions or interruptions. Currently, ADSL technology is considered one of the most reliable ways to provide access to the global network;
5. Low costs for the subscriber when connecting.

Minuses

The main disadvantages include the following:

1. The presence of crosstalk has a high impact on the speed of the Internet, that is, if a significant number of users use one line, the data reception and transmission speed will be low;
2. Low speed of outgoing traffic from the user.

What determines the speed of the Internet?

The main influence on this important parameter is exerted by the quality of the equipment used and wired communication lines. The more taps and the smaller the diameter of the wires, the worse this indicator.

There is also signal attenuation depending on the length of the wired communication channel to the user. The length of the line should not exceed five kilometers. Compared to other existing analog methods of accessing the global network, DSL has the best speed performance, limited mainly by the modem.

Will it be used in the future?

In the near future, the use of DSL technology with modern modems will be widespread due to the minimum number of software problems and high communication reliability. It should be noted that the technology itself continues to evolve. New communication standards are constantly being developed and new models of devices are being produced that do not require frequent maintenance and repair.