Abstract :
There are around 700 million copper pairs in telephony access networks which provide for extensive connectivity of the world´s population. A combination of this existing copper infrastructure and new transmission technologies mean that a new era of universal broadband access can now begin at a fraction of the cost, and in a fraction of the time required for optical access networks. Many major telcos now have a broadband access strategy involving deployment of ISDN, ADSL and VDSL transmission technologies for a new generation of services; and the use of HDSL for reducing costs and connection time for existing services. This paper provides an overview of the most prevalent DSL technologies