Idea of xDSL Technology …!!


xDSL  Technology:

Current copper telephone  lines carry voice- grade communications at speeds up to  28.8 kbps (53.3Kbps with software help.) these lines use the existing telephone network and require no additional hardware or software to access almost any existing network location. This is copper’s main advantage:  instantaneous access to anywhere that the telephone network is. But, this is also a disadvantage:  the entire network is wired for yesterday’s speeds. In a perfect environment, copper speeds would be limited only by the cable attenuation. But, in the existing telephone network, the bandwidth is largely limited by the filters in the network and the network themselves. The upgrade of existing twisted copper wires would serve to enhance the entire network and allow for speeds virtually unheard of server years ago. But, the costs associated with this are extreme; another method would be needed.

This method would have a use existing cables and give notably increased performance. Bellcore, the research entity of several bell operating companies, created the first Digital Subscriber technology and coined the term DSL (Digital Subscriber Line). Bellcore had two main reasons for creating this technology; increased performance and low cost. They aimed for a bandwidth of at lest 2Mbps, but over the current copper network. This would make it both an easy and quick installation, but also a cheap alternative to other network upgrades.

The main reason DSL was invented was to provide high-speed digital access to local corporate and residential customers. DSL’s main concept is to use older copper cables as high-speed digital pipelines. It does this entirely with electronics and software at each endpoint. DSL interfaces are installed at endpoints on the network, while the existing cabling is left untouched.

In a nutshell, DSL compensates for the copper wire’s imperfections. As mentioned previously, attenuation by the cable is a major impedance to network bandwidth. DSL uses software and electronics to ‘’fix’’ the problems with copper wire, creating an overall higher bandwidth data pipe.

What does DSL give us?

  • An almost instantaneous network upgrade.DSL uses the existing copper network to give a marked increase in efficiency.
  • A cheaper alternative to fiber or coaxial cable.
  • DSL’s algorithms make the data transmission more dependable.

DSL provides for several more upgrades to the existing network infrastructure, including increased distances, decreased installation time, immunity to normal cable problems, and the like.

DSL can be used in a variety of environments. The local phone companies could use it for delivering video, audio, and increased bandwidth to both local residential and business customers. Businesses could also use it in a multiple building or even multiple floor setting, to provide increased network bandwidth or allow newer interoffice network technologies (video on demand, conferencing, and more). The possibilities for this cheap network upgrade are as endless as the network it can be applied to.

The Different Flavors of DSL

Several acronyms/ technologies exist when speaking of the Digital Subscriber Line: DSL, DSL, ADSL, HDSL, VDSLVADSL, and BDSL. Table 1 summarizes the acronyms and their meanings. The two most common are ADSL and VDSL.

Table: DSL acronym table.




Digital Subscriber Line (generic)


single line / Symmetric Digital Subscriber Line


Asymmetric Digital Subscriber Line


High bit (data) rate Digital Subscriber Line


Very high data rate Digital Subscriber Line


very high speed Digital Subscriber Line(another term for VDSL)

                                                                                    ——————- Thanks Everyone



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