We explain what ADSL is and the fundamentals of this technology. Also, what it is for, characteristics, advantages and disadvantages.
What is ADSL?
ADSL (from the acronym in English Asymmetric Digital Subscriber List which translates Asymmetric Digital Subscriber Line) is a type of digital data transmission technology and Internet access which consists of transmission through symmetrical copper pairs of telephone lines. That is, a method of accessing the Internet through the telephone line (Switched Telephone Network, PSTN) that does not prevent regular use of the line for calls.
ADSL is a Broadband connection type whose name comes from the fact that the download capacity (from the network to the computer) and upload capacity (from the computer to the network) are not coincident, but rather the first is greater than the second. After all, most Internet users receive more information than they emit.
For ADSL to work it is necessary to have a telephone line and with a modulation system that separates the voice and data frequencies, by installing discriminating filters (called splittersmicrofilters or DSL filters) and an ADSL router provided by the company that provides the service.
This type of urban copper wiring was traditionally implemented, but in the final decades of the 20th century they were gradually replaced by fiberglass, a material that offered better conduction and performance, thus giving rise to even better methods of transmitting digital information, such as the cable modem or the Ethernet.
See also: ISP
What is ADSL for?
Just like other digital transmission systems, ADSL serves as a digital data transmission channel and internet connection.
This means that it is a virtually unlimited source of online information and services with all that this implies. This connection method was key in the massification of the Internet in homes and urban environments during the 90s.
ADSL Features
In an ADSL connection, three independent transmission lines are established:
- Data sending channel Where the user information will be sent to the Internet (upload or load).
- 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 telephone calls will be transmitted.
This separation allows differentiated handling of data and transmission impulses, and can even be improved in the versions known as ADSL2 and ADSL2+, in which a channel is also received for the transmission of subscription television (cable TV) and video. high quality (HD).
Advantages of ADSL
- Does not occupy the telephone line This represents an advantage when installing the service in homes and companies, as it allows the autonomy of both services, something impossible with the dialing method.
- Use traditional infrastructure It does not require new and extensive investments or major works, as it takes advantage of traditional copper wiring.
- Beats dial-up connection It offers a much better speed/price ratio than dialing methods, which in addition to occupying the telephone line generally go at 56 kps, while ADSL can reach 4 mbps (70 times faster).
- Allows core and custom circuits Since it uses telephone cables, each subscriber receives an independent and non-transferable service direct to their home or office.
Disadvantages of ADSL
- It does not operate on all telephone lines It is not enough to have a telephone connection via copper wiring to use ADSL, since this technology has a limit of 3km in line length from the broadcasting center.
- Demand quality 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 exchange and fluctuations in the service flow.
- It is much inferior to fiber optics Fiber optic connections far surpass ADSL in stability and speed.
VDSL
The VDSL or VHDSL (from the acronym in English Very High-bit-rate Digital Subscriber Line or Digital Subscriber Line with a very high transfer rate) is a type of Broadband Internet connection with much higher performance than ADSL representing its evolution or higher step.
This technology consists of use of four channels for data transmission: two for downloading and two for loading, substantially increasing the transmission power of the service.
