ADSL Technology
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ADSL Overview
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Asymmetric Digital Subscriber Line (ADSL), a modem technology, converts existing twisted-pair telephone lines into access paths for multimedia and high-speed data communications. ADSL can transmit up to 6 Mbps to a subscriber, and as much as 832 kbps or more in both directions |
ADSL will play a crucial role over the next ten or more years as telephone companies, and other service providers, enter new markets for delivering information in video and multimedia formats. New broadband cabling will take decades to reach all prospective subscribers. But success of these new services will depend upon reaching as many subscribers as possible during the first few years. By bringing movies, television, video catalogs, remote CD-ROMs, corporate LANs, and the Internet into homes and small businesses, ADSL will make these markets viable, and profitable, for telephone companies and application suppliers alike. |
Why ADSL ?
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Internet bandwidth demand continues to increase. The legacy methods of the Internet access such as dial-up modem or ISDN are not perfectly appropriate for the recent network usage. Although cable modems have greater bandwidth capabilities than the other legacy methods, the bandwidth is shared among all users on a line and the speed will in many cases be slower than ADSL. Broadband fiber-based infrastructure, such as Fiber-to-the-Curb (FTTC) or Fiber-to-the-Home (FTTH), will be the technology of choice in the longer term, but entails increased investment in fiber cabling rebuilding. |
ADSL enables the remote access users to turn existing copper into high-speed network access links. This approach is one of the most attractive solutions to the last mile problems, which are often referred as the bottleneck problems associated with the last mile between Network Service Providers and the users, because the broadband speeds can be achieved over the most universal network infrastructure in the world: ordinary telephone lines. In other words, the most significant difference between ADSL and other high-speed transmission alternatives lies in the number of existing line currently available. |
ADSL Benefits
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ADSL technology is far more advantageous than other access technologies currently available. The benefits of ADSL include: |
Connectivity: Simultaneous Internet and telephone/fax capabilities over a single telephone line. A user is always connected and there is no need to dial up.
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Speed: ADSL can endure the data rate necessary to handle all kinds of applications, such as very high fast data transfer and broadcast video: 1.544 to 9 Mbps downstream, 16Kbps to 1.544 Mbps upstream. |
Cost Effectiveness: Because of the usage of existing copper pairs, the ADSL is a very cost-effective solution for residential users and small businesses. |
Reliability: ADSL operates over the copper-based telephone network that is one of the most robust and proven infrastructures. |
ADSL Recommendations and Standards
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ITU and several other international standardization bodies are involved in the ADSL standardization process. |
ITU-T |
G.992.1 Asymmetrical Digital Subscriber Line (ADSL) Transceivers
G.992.2 Splitterless Asymmetrical Digital Subscriber Line (ADSL) Transceivers
G.994.1 Handshake procedures for Digital Subscriber Line (DSL) Transceivers
G.995.1 Overview of Digital Subscriber Line (DSL) Recommendations
G.996.1 Test procedure for Digital Subscriber Line (DSL) Transceivers
G.997.1 Physical layer management for Digital Subscriber Line (DSL) Transceivers |
ANSI (American National Standard Institute) |
T1.413 Telecommunications - Network and Customer Installation Interfaces - Asymmetric Digital Subscriber Line (ADSL) Metallic Interface |
ETSI (European Telecommunications Standards Institute) |
TS 101 388: Coexistence of ADSL and ISDN-BA on the same pair [ANSI T1.413 - 1998, modified] |
DSL Forum (former ADSL Forum) |
TR-007 Interfaces and System Configurations for ADSL: Customer Premises
TR-019 ADSL Forum Recommendation for Physical Layer of ADSLs with a Splitter
TR-020 ADSL Forum Recommendation for Physical Layer of ADSLs without a Splitter
TR-021 ADSL Forum Recommendation for ATM Layer of ADSLs |
ATM Forum |
af-rbb-0099.000 Residential Broadband Architectural Framework
af-rbb-phy-0101.000 RBB Physical Interfaces Specification |
DAVIC (Digital Audio Visual Council) |
DAVIC 1.2: ATM on ADSL specification |
TTC (Telecommunication Technology Committee) |
JT-G995.1
JT-G992.2
JT-G994.1
JT-G996.1 |
COM One ADSL Solutions
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-> USB CopperSpeed ADSL |
-> PCI CopperSpeed ADSL |
More...
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-> http://www.adsl.com |
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