Maximum internet speed via adsl. What is a connection using ADSL technology. Internet connection via ADSL

ADSL is a technology for asymmetric Internet access. Its structure is an asymmetric system and allows you to work with connections at speeds up to 8 Mbit/s. ADSL technology, the transmission speed of which is calculated to be up to 1 Mbit/s, 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. They first started talking about its 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 a LAN and other network systems.

Modern ADSL technology: operating principle

The network operates on the subscriber's digital line, which provides access to the Internet through telephone channels. But telephone lines use an analog signal to transmit voice messages. An ADSL connection is designed to convert an analog signal into a digital one and transmit 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 At the same time, unlike already outdated Dial-up modems, ADSL-based devices do not block the telephone line and allow you to use digital and analog signals simultaneously.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) is that the subscriber receives a huge amount of data - incoming traffic, and transmits a minimum of information from himself - downward traffic. Input refers to various types of content: video and media files, applications, objects. The downstream sends only important technical information - various commands and requests, emails and other minor 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 of ADSL technology is its cost-effectiveness and cost-effectiveness. The fact is that the same copper ones are used to operate the system. The quantity in them, of course, significantly exceeds the number of similar elements in cable modems. But at the same time, no modernization of switching equipment or 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, it is used special types modems, differing in their structure, design, type of connection:

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

Additional equipment: splitters and microfilters

We must not forget that to connect a gadget such 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 has been made (or can be done) to separate the modem and telephone channels, a splitter is used. In another case, it is necessary to purchase a microfilter, 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 telephone is ensured, which do not interfere with each other and do not create interference. Splitters are compact and will not cause unnecessary inconvenience. The miniature box is equipped with three connectors and is lightweight.

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

1. Choosing a provider. Use this technology At the moment, every provider offers it. Different kinds and tariffs depend on the region, as well as on technical capabilities companies whose coverage area may be limited.
2. Purchase of equipment. Currently, 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, when the document is terminated, 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.
3. Account activation. The provider reserves an account for each client, activation of which may take up to 12 days. However, in most cases, with normal network coverage, the procedure does not require more than a few hours. The provider first checks the phone number for ADSL connectivity. If the access zone of the technology is not enough, then high-speed Internet will not be possible.
4. Equipment setup. At this stage, devices are connected to the telephone line, splitters and microfilters are installed, 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 waits. The technology is constantly being improved, and speeds are increasing, significantly expanding the subscriber's capabilities.
• Wireless connection. To use the ADSL system, you do not need to stretch the cable to the subscriber and install a large number of equipment. The reliability, quality and functionality of the network increases.
• No interference on the telephone line. The ADSL router operates in independent mode and does not create any problems for the phone. You can make calls and travel around the virtual space completely freely.
• Constant 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.

Flaws

1. No crosstalk protection. If several dozen clients are connected to one channel, you won’t have to count on high speed. The more subscribers on one ADSL, the lower the quality of data transmission.
2. Although ADSL technology has disadvantages, they are few. This also includes the minimum speed from the subscriber. ADSL asymmetry has an obvious disadvantage - file transfer from the subscriber will be long and inconvenient. But the technology is intended, first of all, for quick access to the Internet and surfing. In addition, the information transmitted from the subscriber takes up minimal space and does not require a large resource.

Speed ​​and factors influencing 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. Some of them may affect the reliability and quality of the equipment. Therefore, it is best for professionals to install modems and routers.

The main reason for low ADSL connection speed is the quality of the subscriber line. We are talking about the presence of cable outlets, 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 diameter of the wire. The standard length of an ADSL channel does not exceed 5 km - the optimal range for high-speed data transfer.

Speed ​​characteristics

When compared to other Internet connection technologies, ADSL is significantly superior in speed. An analog modem will give a maximum of up to 56 Kbit/s, while ADSL at the dawn of its appearance already made it possible to transmit information at speeds of up to 144 Kbit/s.

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

Technology Outlook

The capabilities 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 broad Internet access without interruptions and software problems, and therefore is a competitor to many other methods of connecting to the Internet.

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

Conclusion

So, we found out what ADSL technology is, what its essence is 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, it does not require constant reconnections and speed restrictions.

Technologies and standards ADSL2 and ADSL2+

ADSL2 and ADSL2+ technologies, providing the ability to implement true solutions. New video applications such as IPTV and VoD require high transmission speeds (over 10 Mbps) towards the user, and ADSL2+ technology can provide them. ADSL2+ transmission speeds reach 24 Mbit/s.

Advantages

ADSL2+ technology also has a number of new features and advantages compared to the older ADSL version. The most important features, such as increased range and transmission speed, line diagnostics, transmission power control, fast connection establishment and improved interoperability, are already integrated on the new BAN, mBAN and ipBAN node cards from the outset. ADSL2+ technology is also ideal for replacing VDSL among home subscribers with more demanding access requirements. Using ADSL2+, video service providers will be able to offer users even 3 simultaneous video programs on one broadband port.

Basic distinctive features and benefits

Improved transmission speed and range parameters

ADSL2 and ADSL2+ use improved modulation, which provides reduced framing overhead, higher coding gains, and also provides improved initialization mechanisms and signal processing algorithms. ADSL2 allows you to increase the data transfer rate in the direction of the user to more than 12 Mbit/s, compared to approximately 8 Mbit/s in the case of ADSL. ADSL2 allows you to increase the loop length by approximately 200 m, or increase the data transfer rate by approximately 50 kbit/s over the same distance for long-distance subscriber lines.

The ADSL2+ standard allows you to double the maximum frequency used to transmit data towards the user - 2.2 MHz instead of 1.1 MHz. This allows the maximum downstream transfer rate to be increased to 25 Mbit/s on telephone lines up to 1500 m long.

Diagnostics and automatic adjustment

Real-time monitoring functions provide real-time information about line quality and noise at both ends of the line. Service providers can use this data to monitor ADSL connection quality and prevent service degradation. In addition, with the help of this data, providers will be able to determine whether a particular user can be provided with services at a higher transfer rate. SELT (without remote end connected) and DELT (with remote end connected) provide the ability to determine the length of the line, the presence of short-circuited and open circuits, wire cross-section and expected capacity before operation. If conditions change in the channel, use new opportunity, which is called smooth transmission rate adjustment (SRA - seamless rate adaptation). This feature allows the ADSL2 system to change the data rate of the connection without interrupting service or causing a bit error.

Advanced power management options

Dual power management modes help reduce power consumption while maintaining ADSL always-on functionality for users. Power mode L2 is for low data rate mode that does not require full bandwidth, and power mode L3 is for standby or sleep mode. This feature can reduce energy consumption by more than 50% for each line.

Quick start

Quick Start Mode reduces initialization time from approximately 10 seconds to less than 3 seconds.

Fully digital mode

This additional option allocates the “telephone” frequency band for data transmission. In this case, the data transfer rate in the upstream direction (from the user to the network) increases by 256 kbit/s, which may be an attractive solution for enterprises that provide voice services over different telephone lines and for which the possibility of increasing the upstream data stream speed is represented by special interest. This capability may also be of interest to service providers who can lease local lines from telecommunications companies on a local loop unbundling (LLU) basis.

Improved equipment interoperability

New modem initialization procedures resolve hardware compatibility issues and provide better performance when ADSL transceivers from different chip vendors are connected.

Other features and functionality

Channeling

ADSL2 channelization capabilities provide support for CVoDSL (CVoDSL), a method of transparently transporting TDM voice traffic over DSL lines. CVoDSL carries voice traffic at the physical layer, allowing analog telephone "lines" to be placed on a DSL circuit and carried in parallel with data traffic, supporting both analog telephone service (POTS) and high-speed Internet access.

Combining multiple lines for higher transfer speeds

The new standards support Inverse Multiplexing for ATM (IMA), developed by the ATM Forum for networks with traditional ATM architecture. Thanks to IMA, ADSL2 integrated circuits can combine multiple copper pairs into a single ADSL link. The result is data transfer speeds over existing copper lines that are comparable to fiber optic lines.

Support for packet network services

Packet network services (eg Ethernet) can be carried over ADSL2 as a complement to ATM.

If you connected to a provider, concluded an agreement and received a modem, then

ADSL modems must be configured disconnected from the telephone line, and the exception is modems connected to the computer via USB port. PVC parameters should be clarified with the provider's technical support. For example, at Rostelecom In most cases VPI-0 VCI-33. In the configuration example we will use exactly these parameters.
Set up an ADSL modem can be done in two ways, either Bridge, or Router. Problems may arise when logging into the modem to configure it.
If you log into the modem using Internet Explorer fails, then need to check IP addresses on the network card (they must be from the same subnet as on the modem) and set the browser settings to default.
For modems with USB Installation of drivers must begin without connecting the modem to the computer until operating system she won’t ask you to do it herself.
The most efficient and easy to configure can be considered the Windows OS with all the basic components installed.
When setting up an ADSL connection, it is better not to launch unknown applications and use antivirus and security programs (Windows Firewall, Firewall, etc.). Also, do not allow your network details (login, password) to become known to strangers.

Instructions for independent ADSL connection:

Equipment required to connect to the network Internet no ADSL

To connect to the Internet using ADSL technology you need:
— Computer:
— ADSL modem;
— Splitter;
A set of cables for connecting the modem to the telephone network and a computer. Computer requirements:
Network card with an Ethernet 10/100Base-T interface (if the modem is with Ethernet), or a USB interface (if the modem is with USB);
Operating system any of the following: Windows XP, Windows 7, Windows 8.

Equipment connection procedure:

1. Connect the splitter to the telephone line;

2. Connect a telephone set and a modem to the splitter;
3. Connect your computer to the modem.

ADSL modem connection diagram:

Installing an ADSL splitter

Connect the connector LINE on a splitter with a telephone socket (line). If you have old-style telephone sockets installed (five-pin), then you will need to purchase an adapter for a Euro connector (RJ11).

ATTENTION: If you have several telephone sockets or parallel telephone sets, then the splitter must be installed before all branches of your telephone line. For stable communication, it is very important that there are no unreliable contacts (twists, etc.) on the telephone line to the splitter and from the splitter to the modem.

Connecting an ADSL modem

Connect the modem connector labeled DSL or WAN with splitter connector with inscription MODEM using the telephone cable supplied with the modem. Connect port LAN on a modem with an Ethernet port on a computer or an Ethernet switch using the Ethernet cable included in the delivery kit. Connect the power adapter and turn on the modem by pressing the " ON/OFF "on the modem.

Connecting a telephone

Using the second cable supplied, connect the telephone to the jack PHONE on the splitter.

ADSL modem being configured in one of two ways: in mode Bridge or in mode Router.

Setting up an ADSL modem in BRIDGE mode

PPP client (Point-to-Point Protocol- a protocol for transmitting data over a dial-up or dedicated communication channel between two participants in a connection) is configured on a computer.

Required basic modem settings:
VPI (Virtual Path Identifier) — ABOUT
VCI (Virtual Circuit Identifier) — 33
Encapsulation type — Bridged IP over ATM LLC SNAP (RFC1483)
Service category — UBR
Power-on mode — Bridge
To set up the modem, you must use the manufacturer's instructions, or the attached brief instructions for your modem (if available).

Setting up an ADSL modem in ROUTER mode

PPP client configured on the modem itself via the web interface.

1. Connect the modem to the splitter and computer as shown in the diagram (see above).
There should be no parallel connections of any devices on the line before the splitter.
2. Before starting to use the modem, it is strongly recommended that you read the user manual that came with your modem.
For a USB modem, install the driver (control program included with the modem on a CD-ROM disk) in accordance with the recommendations of the ADSL modem manufacturer.
Create a new or change an existing network connection (Follow the following steps to set up a computer running Windows XP).
On the menu Start [Start] select Settings and then Network connections [Network Connections].
In the window Network connections right click on " Connection via local network ", then select Properties.
On the " Are common» this menu, highlight the item Internet Protocol (TCP/IP)
Click on the button Properties.
Set options in the window Internet Protocol (TCP/IP) :
IP address:
192.168.1.2 (for D-Link 192.168.0.2)
Subnet mask:
255.255.255.0
Main gate:
192.168.1.1 (for D-Link 192.168.0.1)
Primary DNS server address:
192.168.1.1 (for D-Link 192.168.0.1)
Secondary DNS server address:
8.8.8.8

3. To configure the modem, launch an Internet browser (Internet Explorer, Google Chrome, Opera, Firefox, Safari)

Type in the address bar http://192.168.1.1 (for D-Link http://192.168.0.1)
To access the modem configuration, enter your login and password to access the modem configuration interface - usually this is admin / admin, Admin / Admin or admin / 1234 .
After this you will be taken to modem web interface.
When configuring the modem, set the following parameters.
DSL protocol — PPPoE(RFC2516)
DSL modulation — Automatic
Network Protocol — PPP over Ethernet LLCSNAP (RFC2516)
Peak Cell Rate — Use Line Rate
Service category — UBR without PCR
Encapsulation Type — LLC/SNAP
VPI — 0
VCI — 33
User name (login)— Name provided by the operator when concluding the contract
Password— Password provided by the operator when concluding the contract
Save the modem settings configuration - Save settings.

These days, almost everyone needs access to the Internet. Be it work, entertainment, communication - the global network has entered our lives everywhere. To provide Internet access at home or in the office, you need a modem that will allow you to connect all the necessary devices to the network. In large cities, providers offer fiber optic and fiber coaxial systems that allow you to get a fast and stable connection. However, to install such cables, it is necessary that the number of users allows filling the entire bandwidth of the cable - otherwise it is simply not profitable. Therefore, the possibility of such a connection is not provided by businesses everywhere. This is especially true for small cities, towns and villages. What to do if such services are not provided, but you still need the Internet?

There are different options, and one of the best is to use twisted pair telephone wires. Many will remember with horror a phone not working while using the Internet. However, technology has long gone far ahead. Today, xDSL technologies are the most common and effective. DSL stands for digital subscriber line. This technology allows you to achieve fairly high data transfer speeds over copper pairs of telephone wires, without occupying the phone. The fact is that voice transmission uses a frequency range from 0 to 4 kHz, while copper telephone cable can transmit signals with a frequency of up to 2.2 MHz, and it is the section from 20 kHz to 2.2 MHz that xDSL technology uses . The speed and stability of such a connection is affected by the length of the cable, that is, the farther the telephone node (or another modem in the case of creating a network) is located from your modem, the lower the data transfer speed will be. The stability of the network is due to the fact that the data flow goes from the user directly to the node, its speed is not affected by other users. An important factor: to provide an xDSL connection, there is no need to replace cables, which makes it theoretically possible to connect to the Internet wherever there is a telephone (depending on the availability of such a service from the provider).

An xDSL modem will be the link between your phone cable and your devices (or router), but when choosing a specific model, you need to consider a number of characteristics that are right for you.

What are the differences between xDSL modems?

xDSL technologies

In the acronym xDSL, the “x” represents the first letter of DSL technology. xDSL technologies differ in signal transmission distance, data transmission speed, and also in the difference in transmission speeds of incoming and outgoing traffic.

ADSL technology translates to asymmetric digital subscriber line. This means that the transfer speed of incoming and outgoing data is different. In this case, the data reception speed is 8 Mbit/s, and the transmission speed is 1.5 Mbit/s. Wherein maximum distance from the telephone exchange (or other modem in the case of creating a network) is 6 km. But the maximum speed is possible only at a minimum distance from the node: the further away, the lower it is.

ADSL2 technology makes much better use of wire bandwidth. Its main difference is the ability to distribute information over several channels. That is, it uses, for example, an empty outgoing channel when the incoming channel is overloaded, and vice versa. Thanks to this, its data reception speed is 12 Mbit/s. The transmission speed remains the same as in ADSL. In this case, the maximum distance from a telephone exchange (or other modem) is already 7 km.

ADSL2+ technology doubles the speed of the incoming data stream by increasing the usable frequency range to 2.2 MHz. Thus, the data reception speed is already 24 Mbit/s, and the transmission speed is 2 Mbit/s. But such a speed is only possible at a distance of less than 3 km from the node - then it becomes similar to ADSL2 technology. The advantage of ADSL2+ equipment is that it is compatible with previous ADSL standards.

SHDSL technology is a standard for high-speed symmetric data transmission. This means that the reception and upload speeds are the same - 2.3 Mbit/s. Moreover, this technology can work with two copper pairs - then the speed doubles. The maximum distance from the telephone exchange (or other modem) is 7.5 km.

VDSL technology has the maximum data transfer speed, but is significantly limited by the distance from the node. It works in both asymmetric and symmetric modes. In the first option, the data reception speed reaches 52 Mbit/s, and the transmission speed – 2.3 Mbit/s. In symmetric mode, speeds up to 26 Mbps are supported. However, high speeds are available up to 1.3 km from the node.

When choosing an xDSL modem, you need to focus on the distance to the telephone exchange (or other modem). If it is small, you can safely focus on VDSL, but if the node is far away, you should choose ADSL2+. If you have two copper pairs of wires, you can also pay attention to SHDSL.

Annex Standards

Annex is a type of ADSL standards for transmitting high-speed data in conjunction with analog telephony (regular telephone).

The Annex A standard uses frequencies from 25 kHz to 138 kHz to transmit data, and from 200 kHz to 1.1 MHz to receive data. This is the usual standard for ADSL technology.

The Annex L standard allows you to increase the maximum communication distance to 7 km thanks to increased power at low frequencies. But not all providers use this standard due to interference.

The Annex M standard allows you to increase the speed of the outgoing stream to 3.5 Mbit/s. But in practice, connection speeds range from 1.3 to 2.5 Mbit/s. For an uninterrupted connection, this standard requires an undamaged telephone line.

DHCP server

The abbreviation DHCP stands for Dynamic Host Configuration Protocol. A DHCP server is a program that allows you to automatic setup local computers for network work. It provides clients with IP addresses (unique identifiers of a device connected to a local network or the Internet), as well as Extra options, necessary for working on the network. This will allow you not to manually register an IP, which will make your work on the network easier. However, please note that for devices such as network printers and permanent remote access to the computer using special programs A statistical rather than a dynamic IP will be desirable, since constantly changing IP will cause difficulties.

USB ports

Today, there are two options for organizing an Internet connection using ADSL technology: via a USB port and via an Ethernet port.
An external USB ADSL modem is connected to a computer via a USB port. It receives power from the computer. The advantages of such modems: low cost and ease of use. The disadvantages include not being compatible with all computers, the need to regularly reinstall drivers, and working with only one device.
An ADSL modem connected to the device via an Ethernet port will work more stable. But to be used with multiple devices, it must have a router function or Wi-Fi technology.

Setup and management

Configuring and managing modems is most often carried out using three technologies: Web interface, Telnet and SNMP.
The web interface is a function that allows configuration and management via a computer browser. This option will be sufficient for home use of the modem.

Telnet is a network protocol for remotely accessing a computer using a command interpreter. With its help, you can configure the modem from devices not connected to it. This is useful for small modem circuits at home and in the office.

SNMP is a standard Internet protocol for managing devices on IP networks operating on the TCP/IP architecture (a means for exchanging information between devices connected to a network). Using the SNMP protocol software to manage network devices, it can access information stored on managed devices. Due to this, it is most often used when building office networks.

Criterias of choice

xDSL modems differ in a number of characteristics, the most important of which are the maximum distance from the telephone exchange, the speed of data reception and transmission, the presence of symmetric or asymmetric transmission. Understanding under what conditions and how exactly the modem will be used, you can choose the device that is right for you.

Let us remind you that when choosing an xDSL modem, it is important to know the characteristics of the telephone network: the length of the cable to the telephone exchange, the number of copper pairs of the cable and its quality, the offers and capabilities of the provider. It is important that there is no interference on the line, which is caused by the intersection of cable pairs or its poor quality.

We have distributed xDSL modems based on user needs.

To connect to the Internet using xDSL technology on one device It will be enough to purchase an inexpensive USB modem that supports suitable technology (for example, ADSL2+ or VDSL).

To create an Internet network at home or in a small office It is better to pay attention to xDSL modems connected via an Ethernet port. The choice of technology again depends on the capabilities of the telephone network.

To create a large office network with a chain of modems at distances of up to 3 km worth choosing among

04. 09.2017

Blog of Dmitry Vassiyarov.

What is ADSL - old but current method connections

Hi all.

You can't live without the Internet now. Therefore, anyone to modern man It’s worth knowing about the different options for connecting it in order to choose the one that’s right for you. For these reasons, I will tell you about what ADSL is. What if you like this way of connecting to the World Wide Web? If not, you will simply be more knowledgeable about Internet technologies. In any case, after reading the article you will win ;).

Introduction to the xDSL family

In the mid-90s, a new family was born, and not just any simple one, but digital technologies that use a telephone line to connect to the Internet. It is called DSL, which means “digital subscriber line” (digital subscriber line). The abbreviation is usually preceded by an "x" to hide a specific member of that family.

There are quite a lot of them, but one of the most popular nowadays is Asymmetric. So our further conversation will be about ADSL. As the name implies, its feature is asymmetry. We are talking about the uneven distribution of downstream and upstream traffic.

The speed of the second one is lower. Practice shows that the first digit is more important for users. Because the volume of incoming traffic always exceeds the amount of outgoing traffic.

ADSL physical design

So what is adsl? To understand the essence of our conversation, you must understand what ADSL actually is. Connecting to the network using this technology is performed through a telephone line and 2 modems (1 is located at the subscriber, the other at the provider).

There is usually an intermediary between the telephone cable socket and the user's modem - a splitter. It has 1 input for connecting a telephone line and 2 outputs - for the telephone itself and the modem. The splitter also eliminates communication interference and ensures the safety of devices from high-voltage pulses thanks to its inductors and electrical protection circuits on varistors.

By the way, there are modems that allow you to additionally connect one that distributes Wi-Fi.

A modem is no problem for your phone

Representatives of the “old school”, who remember how connecting to the Internet via telephone in the 1990-2000s, do not rush to write off ADSL. For those who don’t remember this, let me explain: in those days you could either go online or talk on the phone - one of two things.

But in asymmetric technology this drawback is eliminated. The fact is that talking on the phone takes up a tiny percentage of the line's capabilities. Smart people figured out to use the rest of the channel to access the network so that one does not interfere with the other.

For undemanding voice communications, the lowest frequency band is used, for the Internet - everything else. In particular, the phone uses the range 400 - 3500 Hz, incoming traffic - 26000 - 138000 Hz, outgoing traffic - from the last digit to 1.1 MHz.

Which line is suitable for the Internet?

Connecting to the network via ADSL is cost-effective. Since you don’t have to buy a modem, but rent it from a provider, and you don’t have to lay new cables. But this is only if the telephone company provides Internet service. In addition, not just any line will do the job. It must meet the following requirements:

• The loop resistance is no more than 1200 Ohms, and the insulation resistance is no less than 40 MOhms;
• loop capacity - maximum 300 nanofarads;
• capacitive asymmetry - maximum 10 nF;
• signal attenuation: good - 5-20 decibels, in the range from the last digit to 30 dB there are glitches, and at 31-40 dB synchronization may be lost;
• noise level: from -65 dB to -55 dB - excellent, up to -35 dB - good, up to -21 dB there may be malfunctions, and if lower, the equipment will not work.

The quality of the cable also matters. It is best to use shielded twisted pair cable. Often the telephone is connected through a single-pair distribution wire (SDC), especially in older houses. Which, of course, is not suitable for new technologies.

Data transfer rate

The primary question when choosing a method to connect to the Internet is what is its speed? In comparison with others modern types ADSL connections “smoke on the sidelines”, although it is considered high-speed. Compare for yourself.

The latest generation of this technology is 2++. Its maximum input speed is 48 Mbit/s, output speed is 3 Mbit/s. While the currently popular family can offer customers an incoming traffic speed of 5 Gbit/s, although 1 Gbit/s remains more affordable, and, nevertheless, this is much more than the ADSL maximum.

For these reasons, a leased line is in greater demand than modem technologies. However, ADSL is still showing its ability to compete. For example, in government institutions and other enterprises where they cannot do without landline phones, it is convenient and profitable to use their lines for the Internet, because high speed is not needed in such a situation.

Basically, that's all I wanted to say about what adsl is.

You are always welcome on my blog page.