VDSL/VHDSL (Very High Bitrate Digital Subscriber Line) is an improved version of the technology, ADSL or Asymmetric Digital Subscriber Line, which we use to connect to the internet. They are different in how they are implemented so you probably cannot use the equipment of one for the other. The most significant difference between the two technologies that is most relevant to the use is speed. ADSL can reach maximum speeds of 8mbps download and 1mbps for upload. In comparison, VDSL can have up to 52mbps for download and 16mbps for upload.
Because of the extremely high speeds that VDSL can accommodate, it is being looked at as a good prospective technology for accommodating high bandwidth applications like VoIP telephony and even HDTV transmission, which ADSL is not capable of. Another very useful feature of VDSL stems from the fact that it uses 7 different frequency bands for the transmission of data. The user then has the power to customize whether each frequency band would be used for download or upload. This kind of flexibility is very nice in case you need to host certain files that are to be downloaded by a lot of people.
The most major drawback for VDSL is the distance it needs to be from the telephone exchange. Within 300m, you may still get close to maximum speed but beyond that, the line quality and the speed deteriorates rather quickly. Because of this, ADSL is still preferable unless you live extremely close to the telephone exchange of the company that you are subscribed to. Most VDSL subscribers are companies who need a very fast server and would often place their own servers in very close proximity.
Due to the limitations of VDSL and its high price, its expansion is not as prolific as that of ADSL. VDSL is only widespread in countries like South Korea and Japan. While other countries also have VDSL offerings, it is only handled from a few companies; mostly one or two in most countries. In comparison, ADSL is very widely used and all countries that offer high speed internet offer ADSL.
DSL technology known as very high bit-rate DSL (VDSL) is seen by many as the next step in providing a complete home-communications/entertainment package. There are already some companies, such as U.S. West (part of Qwest now), that offer VDSL service in selected areas. VDSL provides an incredible amount of bandwidth, with speeds up to about 52 megabits per second (Mbps). Compare that with a maximum speed of 8 to 10 Mbps for ADSL or cable modem and it's clear that the move from current broadband technology to VDSL could be as significant as the migration from a 56K modem to broadband. As VDSL becomes more common, you can expect that integrated packages will be cheaper than the total amount for current separate services.
In this article, you'll learn about VDSL technology, why it's important and how it compares to other DSL technologies. But first, let's take a look at the basics of DSL.
A standard telephone installation in the United States consists of a pair of copper wires that the phone company installs in your home. A pair of copper wires has plenty of bandwidth for carrying data in addition to voice conversations. Voice signals use only a fraction of the available capacity on the wires. DSL exploits this remaining capacity to carry information on the wire without disturbing the line's ability to carry conversations.
Standard phone service limits the frequencies that the switches, telephones and other equipment can carry. Human voices, speaking in normal conversational tones, can be carried in a frequency range of 400 to 3,400 Hertz (cycles per second). In most cases, the wires themselves have the potential to handle frequencies of up to several-million Hertz. Modern equipment that sends digital (rather than analog) data can safely use much more of the telephone line's capacity, and DSL does just that.
VDSL could change the face of E-commerce by allowing all types of media to run smoothly and beautifully through your computer.
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