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Definition of ADSL
- 1 Meaning of ADSL
- 2. Definition of ADSL
- 3 Concept of ADSL
1 Meaning of ADSLAsymmetric digital subscriber line, 1 ADSL (Asymmetric Digital Subscriber Line English acronym) is a type of DSL line technology. Consists of analog digital data transmission supported by the symmetrical pair of copper that takes the conventional telephone line or subscriber line, 2 when the line length does not exceed the 5.5 km from the telephone exchange, or there are no other services by the same cable that might interfere.
It is a technology of broadband Internet access, which means faster than a connection via a modem in data transfer, since the modem uses the voice band and therefore prevents the service voice when in use and vice versa. This is achieved through a modulation of the data signals in a band of frequencies higher than used in conventional telephone conversations (300-3400 Hz) function that performs the ADSL router. To avoid distortions in the transmitted signals, the installation of a filter (called a splitter or Screener) which is in charge of separating the conventional telephone signal modulated signals of the ADSL connection is required.
This technology is called asymmetric because the ability to download (from the network to the user) and data upload (in reverse order) do not match. ADSL technology is designed so that the ability to drop (download) is greater than the ascent, which corresponds to the use of the internet by the majority of end users, who receive more information which they send (or downloading more than it going up).
An ADSL line establishes three communication channels, which are sending data, the data reception and normal telephone service.
Currently, phone companies are implementing enhanced versions of this technology such as ADSL2 and ADSL2 + capable of providing television and by the telephone pair high-quality video, which is a tough competition between telephone operators and the cable, and the emergence of integrated offerings of voice, data and television, from a line and within a single companyto provide these three services of communication. The use of a higher bandwidth for these services further limits the distance that can be operated, by the pair of strings.
ADSL2 and ADSL2 + incorporate mechanisms of modulation and advanced physical resources management, so that they not only increase the capacity of conventional ADSL of 8 mbps to 12 and 24 mbps respectively, they introduced improvements to avoid interference or noise and lessen the effects of attenuation, hence distances of up to 9 Km can be achieved.
ADSL is a technology that uses the copper pair and has less bandwidth than other technologies such as cable and Metro Ethernet, whose urban wiring is made up of strands of optical fiber instead of the copper pair implemented predominantly in the decades of 1950 and 1960.
2. Definition of ADSLThe acronym ADSL is today a very popular concept at the behest of technology and particularly the Internet and corresponding to the following concept in the English language: asymmetric digital subscriber line, which in terms of our language concerned: asymmetric digital subscriber line. Because ADSL is a type of technology that allows internet access just band wide, to be more specific.
Basically ADSL works by analog transmission with support on the symmetrical copper pair that contains the traditional phone any subscriber installation, i.e. in this manner transmits digital data. It should be noted, that this connection is valid when the 5.5 kilometers long distance does not exceed from the place of installation regarding central telephony or not mediate other services through the same cable and that could interfere with the passage of information.
Speed has this technology is far superior to that provides a connection through a modem and this is because the modem needs a voice band and then this causes that the telephone and internet can not be used at the same time.
Then, in ADSL three communication channels, exist on the one hand sending data, by another receiving these and finally telephony service.
With the Mission of alleviating the typical distortions of signal, what I do is install a filter that especially focuses on dividing telephone and internet signals.
Another issue to highlight is that this type of technology is designed so that the data download speed is many faster than the rise, since internet users use it mostly to get info.
The main innovations associated with this technology include companies which control it and steer are getting to establish much newer versions that already allow the arrival of television and video by the same cable.
3 Concept of ADSL
What is ADSL?The initial functionality of the telephone network has been progressively extended. The initial objective was to offer telephony, but their use for sending of phases and the interconnection of computers, especially via the Internet has become widespread since the early 1990s. However, the traditional 56 Kbps (V.90 on the RTB (basic telephone network) modems), and 64 or 128 Kbps on ISDN (Integrated Services Digital Network), are insufficient for Internet access of the majority of home users, increasingly accustomed to enjoy services and multimedia content with large bandwidth requirements.
The technological to the phone operators challenge fixed was to find a way to take advantage of the huge investments made in the telephone subscriber loop and, simultaneously, to eliminate bottleneck for access the Internet, corporate LAN interconnect, offering à la carte and on-demand video, and enjoy the wide range of interactive and multimedia services where the telecommunication operators have been long. The technology suitable to solve this problem has been ADSL, conceived by Bellcore in 1989, but several years of studies and pilot tests, having been opened for the first time to the public in the United States during 1997. Spain was the first country in Europe to introduce ADSL as means of bringing flat rate 24 hours for access to the Internet, beginning its commercial deployment in September 1999.
How and when using ADSL?The technology ADSL (Asymmetric Digital Subscriber Line) or asymmetric digital subscriber line, is a technology for modems, providing asymmetric access and high speed through the copper pair currently installed on offices and homes of the users of the RTB (or ISDN, which is also compatible). With ADSL were traditionally achieved descending (the central until the user) data transmission speeds of up to 1.5 Mbps over distances of 6 Km, and up to 8 Mbps for distances of 3 km. Maximum downstream speeds (from the user to the central), going 16-640 Kbps, about the same sections. Actual speed depends on, however, the quality of line of copper and the limitations placed by the operator according to the contracted subscriber rate. Reached distances are suitable to cover 90% of the subscribers of the RTB.
ADSL access system is composed of two modems at each end of the telephone line, creating three channels of information: one down at high speed, another rising average speed duplex, and basic telephone service. the latter, is separated from the digital modem through filters, thus ensuring the continuity of the telephone service before a crash or failure of the modem, which is an advantage over ISDN. To as in ISDN and the rest of broadband, users of ADSL Internet access technologies can be used simultaneously the telephone and Internet. In the operator station modems tend to be arranged in racks, and are connected to the Internet or other data networks using an Ethernet link, a gigarouter IP or ATM switch.