What is ADSL?
The ADSL (from the abbreviations in Asymmetric Digital Subscriber List that translates Asymmetric Digital Subscriber Line) is a type of technology of digital data transmission and Internet access , which consists of the transmission through symmetrical pairs of telephone line copper. This is, a method of accessing the Internet through the telephone line (Telephone Network Switched, PSTN) that does not prevent the regular use of the line for calls.
The ADSL is a type of broadband connection , whose name comes from the fact that the capacity of download (from the network to the computer) and load (from the computer to the network) are not coincident, but the first is greater than the second. After all, most Internet usersreceive more information than they emit.
For the ADSL to work, it is necessary to have a telephone line and a modulation system that separates the frequencies of the voice and data , by installing discriminating filters (called splitters , microfilters or DSL filters) and an ADSL router. provided by the company that provides the service.
This type of copper urban wiring was traditionally implemented, but in the final decades of the 20th century it was gradually replaced by fiberglass, a material that offered better driving and performance, thus accommodating even better methods of digital information transmission, such as the cable modem or the Ethernet.
See also: ISP .
What is ADSL for?
As with other digital transmission systems, ADSL serves as a channel for the transmission of digital data and connection to the Internet .
This means that it is a virtually unlimited source of information and online services , with all that this implies. This method of connection was key in the massification of the Internet in homes and urban environments during the 1990s.
Characteristics of ADSL
In an ADSL connection , three independent transmission lines are established:
- Data transmission channel . Where the user’s information will be sent to the Internet ( upload or upload).
- Data reception channel . Where the information will be received from the Internet ( download or download). It will be the widest of the three channels.
- Regular telephone service channel . Where the telephone calls will be transmitted.
This separation allows a differentiated handling of data and transmission pulses, and can even be improved in the versions known as ADSL2 and ADSL2 +, in which a channel for the transmission of subscription television (cable TV) and video is also received. of high quality (HD).
Advantages of ADSL
- It does not occupy the telephone line . This represents an advantage when installing the service in homes and companies, since it allows the autonomy of both services, something impossible with the dialing method.
- Use the traditional infrastructure . It does not require new and extensive investments or large works, because it takes advantage of traditional copper wiring.
- It exceeds the dial-up connection . It offers much better speed / price ratio than the dialing methods, which in addition to occupying the telephone line are usually at 56 kps, while the ADSL can reach 4mbps (70 times faster).
- It allows central and customized circuits . Since it uses telephone cables, each subscriber receives an independent and non-transferable service directly to his home or office.
Disadvantages of ADSL
- It does not operate on any telephone line . It is not enough to have a copper wire telephone connection to use the ADSL, since this technology has a limit of 3km of line length from the emission center.
- It demands quality of copper . In countries where this material is expensive or scarce, the service may not be as economical as in others.
- It depends on external factors . The quality of the service is subject to the quality of the cables, the distance from the power station and fluctuations in the service flow.
- It is very inferior to optical fiber . The fiber optic connections far exceed the ADSL stability and speed.
The VDSL or VHDSL (of the abbreviations in English Very High-bit-rate Digital Suscriber Line or Line of Subscriber Digital of very high rate of Transfer) is a type of connection to Internet by Broadband of very superior performance to the ADSL , representing its evolution or superior step.
This technology consists of the use of four channels for the transmission of data : two for the download and two for the load, substantially increasing the transmission power of the service.