Asymmetric Digital Subscriber Lines

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|Electronics(ECE)/Electrical(EEE)/Instrumentation(EI or AE&I) Seminar Report | ASSYMETRIC DIGITAL | |SUBSCRIBER LINE |

ASSYMETRIC DIGITAL SUBSCRIBER LINE

ABSTRACT

ABSTRACT

Digital Subscriber Lines (DSL) are used to deliver high-rate digital data over existing ordinary phone-lines. A new modulation technology called Discrete Multitone (DMT) allows the transmission of high speed data. DSL facilitates the simultaneous use of normal telephone services, ISDN, and high speed data transmission, e.g., video. DMT-based DSL can be seen as the transition from existing copper-lines to the future fiber-cables. This makes DSL economically interesting for the local telephone companies. They can offer customers high speed data services even before switching to fiber-optics.

DSL is a newly standardized transmission technology facilitating simultaneous use of normal telephone services, data transmission of 6 M bit/s in the downstream and Basic- rate Access (BRA). DSL can be seen as a FDM system in which the available bandwidth of a single copper-loop is divided into three parts. The base band occupied by POTS is split from the data channels by using a method which guarantees POTS services in the case of ADSL-system failure (e.g. passive filters).

INDEX
PAGE NO.

CHAPTER 1

INTRODUCTION 06

1.1 Different variants of DSL 07
1.2 What makes DSLpopular 08
1.3 What are the benefits. 08
CHAPTER 2

ASYMMETRIC DIGITAL SUBSCRIBER LINE (ADSL). 10

2.1. The components of an ADSL network include a 11
TELCO and a CPE

CHAPTER 3

ADSL CAPABILITIES. 13

CHAPTER 4

ADSL TECHNOLOGY. 16

4.1. ADSL transceiver – network 17

CHAPTER 5

METHODS TO SPLIT THE SIGNAL. 20

5.1 Carrier less amplitude/phase(cap). 20
5.2 Discrete Multi tone 21
5.3. Splitting the signal: filters 22

CHAPTER 6.

ADSL EQUIPMENT. 24

6.1 DSL Equipment: DSLAM 25

CHAPTER 7

STANDARDS AND ASSOCIATIONS. 27

CHAPTER 8

DISTANCE LIMITATIONS. 29

CHAPTER 9

DSL FUTURE. 32

CHAPTER 10

APPLICATIONS. 34

CHAPTER 11

CONCLUSION 36

REFERENCE 37
APPENDIX

CHAPTER-1

INTRODUCTION

1INTRODUCTION

The past decade has seen extensive growth of the telecommunications industry, with the increased popularity of the Internet and other data communication services. While offering the world many more services than were previously available, they are limited by the fact that they are being used on technology that was not designed for that purpose.

The majority of Internet users access their service via modems connects to the Plain Old Telephone System (POTS). In the early stages of the technology, modems were extremely slow by today's standards, but this was not a major issue. A POTS connection provided an adequate medium for the relatively small amounts of data that required transmission, and so was the existing system was the logical choice over special cabling.

Technological advances have seen these rates increase up to a point where the average Internet user can now download at rates approaching 50Kbps, and send at 33.6Kps. However, POTS was designed for voice transmission, at frequencies below 3kHz, and this severely limits the obtainable data rates of the system. To increase performance of new online services, such as steaming audio and video, and improve general access speed, the bandwidth hungry public must therefore consider other alternatives. Technologies, such as ISDN or cable connections, have been in development for sometime but require special...
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