DSL - Digital Subscriber Line An Overview Presented by Team 1 November 17, 2001

ADSL Contents n Origins of ADSL n Definition n ADSL Standards – US n Typical ADSL Installation n Technical Description n Evaluation n A View to the Future

Origins of ADSL n Availability of Cabling n Need for Faster Communication n Internet EXPLOSION! n Expense of ISDN n Emergence of Telecommuting n New Applications

Definition n Asymmetric DSL (ADSL) “a modem technology that converts existing twisted pair telephone lines into access paths for multimedia and high speed data communications.” Source:"ADSL Tutorial: Twisted Pair Access to the Information Highway,"

ADSL Standards - US n n ANSI T1E1 working group n n ITU-T Study Group 15 n n ADSL Forum – – Recommends end-to-end ADSL architectures, including the higher layer protocols needed to make ADSL systems useful products.

Typical ADSL Installation

Technical Description General n Frequency:Above 25kHz –POTS Below 4kHz n Modulation: –DMTDiscrete Multi-tone –CAPCarrier-less Amplitude/ Phase Modulation –QAMQuadrature Amplitude Modulation n Medium:Unshielded Twisted Pair –24 AWG (~.5m) –26 AWG (~.4m)

Technical Description Transmission Rates n Class I6,175 Mb/s –6,000 ft26 AWG loops n Class II4.632 Mb/s –8,000 ft26 AWG n Class III3.088 Mb/s –12000 ft24 AWG – 9000 ft26 AWG n Class IV1.544 Mb/s –18000 ft26 AWG

Installation Components. Source: Paradyne, Inc.

ADSL - An Evaluation n Targeted Marketplace n Chief Competitors n Price Considerations n Economy n Other Barriers

ADSL - A View to the Future n Interim Strategy –Copper –Cable –Fiber n Telecommunications Shake- Out n Emergence of True Wireless Solutions