Copyright © Philip M. Parker, INSEAD. Terms of Use.
| Domain | Definition |
Computing | ADSL Asymmetric Digital Subscriber Line. Source: The Free On-line Dictionary of Computing. |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide.As compared to other forms of DSL, ADSL has the distinguishing characteristic that the data can flow faster in one direction than the other, i.e., asymmetrically. Providers usually market ADSL as a service for people to connect to the Internet in a relatively passive mode: able to use the higher speed direction for the "download" from the Internet but not needing to run servers that would require bandwidth in the other direction.
ADSL can use any of a variety of modulation techniques, but the ANSI and ETSI standards use DMT modulation schemes.
Downstream rates start at 256 kbit/s and typically reach 2 Mbit/s but can go as high as 8 Mbit/s over short ranges (so-called VDSL). Upstream rates start at 64 kbit/s and typically reach 256 kbit/s but can go as high as 768 kbit/s. The name ADSL Lite is sometimes used for the slower versions.
Because of the relatively low data-rate (compared to optical backbone networks) ATM is an appropriate technology for multiplexing time-critical data such as digital voice with less time-critical data such as Web traffic; ATM runs widely over ADSL technology to ensure that this remains a possibility.
ADSL service providers may offer either static or dynamic IP addressing. Static addressing is preferable for people who may wish to connect to their office via a virtual private network, for some Internet gaming, and for those wishing to use ADSL to connect a Web server.
UK
In the United Kingdom, users had to live within 3.5 kilometers of the local telephone exchange to receive ADSL, but the range has grown to 5.5 kilometers thanks to RADSL (Rate Adaptive Digital Subscriber Line), although users with RADSL will have a lower upstream rate.The typical home ADSL connection in the UK has 512 kbit/s downstream, and 256 kbit/s upstream (it may run slower if the user has RADSL), with a 50:1 contention ratio. Packages designed for offices or businesses have a 20:1 contention ratio and range from 512 kbit/s to 2 Mbit/s in downstream speed.
See Also
- See DSL for further details and other varieties.
- digital subscriber line access multiplexer
ADSL standards
- ITU G.992.3
- ITU G.992.4
- ITU G.992.5
External links
- DSL Forum - promotional trade organization for the ADSL industry
- adslguide.org.uk
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Asymmetric Digital Subscriber Line."
(From Wikipedia, the free Encyclopedia)
Digital Subscriber Line, or DSL, refers to a family of technologies that provide a digital connection over the copper wires of the local telephone network.
As of 2003, DSL provides the principal competition to cable modems for providing high speed Internet access to home consumers.
How it works
When the telephone system was designed, it was intended for voice calls and, for reasons of economy, it was designed to transmit over a frequency range from around 300Hz to 3 to 4kHz (although human speech can range up to around 15kHz, it can easily be understood if limited to this range).However, the local loop of copper telephone connections to individual subscribers can usually communicate using a much wider range of frequencies, ranging from these low frequencies up to 200 - 800 kHz, depending on the quality of the circuit and the sophistication of the equipment.
DSL services were devised as a means of overcoming the restriction on the amount of data that could be transmitted over the "voiceband" (see Shannon capacity), by using these additional frequency ranges.
While DSL services often reserve the 0.3 - 4 kHz band for voice calls over the "plain old telephone service" (POTS), the frequencies above and below this range can be used to transmit data.
A DSL connection takes place between equipment of the subscriber and the telephone exchange, with some other protocol used between the exchange and whoever the subscriber really wants to connect to, typically an Internet service provider. This differs from a normal telephone connection, where the public telephone network links subscribers to each other.
Equipment
The subscriber end of the connection consists of a DSL modem. This converts data from the digital electronic pulses used by computers into a digital audio stream of a suitable frequency range for the particular DSL variant in use.In addition the subscriber may need to install a passive electronic filter (known variously as a "splitter" or "filter" or "micro-filter") if using the POTS service on the same line (and possibly also to improve the DSL termination and prevent echoes). This ensures that the DSL modem and the telephone only receive the frequencies they are designed to handle. Subscribers can plug a filter into an existing telephone socket when using a "wires-only" service; or alternatively the DSL provider may install it.
At the exchange a digital subscriber line access multiplexer (DSLAM) terminates the DSL circuits and aggregates them, where they are handed off onto other networking transports. It also separates out the voice component.
Protocols and Configurations
Many DSL technologies implement an ATM layer over the low-level bitstream layer to enable the adaptation of a number of different technologies over the same link.DSL implementations may create bridged or routed networks. In a bridged configuration, the group of subscriber computers effectively connect into a single subnet. The earliest implementations used DHCP to provide network details such as the IP address to the subscriber equipment, with authentication via MAC address or an assigned host name. Later implementations often use PPP over ethernet or ATM (PPPoE or PPPoA, also known as PPPoATM), with authentication with a userid and password and using PPP mechanisms to provide network details.
DSL Technologies
The reach-restraints (line length from Central Office to Subscriber) reduce as data rates increase, with technologies like VDSL providing short-range links (typically "fibre to the curb" network scenarios).Example DSL technologies (sometimes called xDSL) include:
- ISDN (pre-dates the use of the term DSL)
- IDSL (ISDN Digital Subscriber Line, a data-only ISDN variant)
- ADSL (Asymmetric Digital Subscriber Line)
- HDSL (High Bit Rate Digital Subscriber Line)
- RADSL (Rate Adaptive Digital Subscriber Line)
- SDSL (Symmetric Digital Subscriber Line, a standardised version of HDSL)
- VDSL (Very high speed Digital Subscriber Line)
- G.SHDSL (ITU-T Standardised replacement for early proprietary SDSL)
See also
- Modem
- COFDM
External links
- ANSI Working Group T1E1.4, a standards group for DSL
- DSL Forum, a promotional trade organization for the ADSL industry
- DSL HOWTO for Linux
- Howstuffworks.com; "How DSL Works"
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Digital Subscriber Line."
| The following table is compiled from various sources, across various languages. When English abbreviations or acronyms come from a non-English source, this is noted. | |||
| Entry | Source | Expression | Field |
ADSL | Danish | Asymmetrisk digitalt abonnentkredsløb | Post & Telecom |
ADSL | Dutch | Assymmetric digital subscriber loop | Electrical Engineering |
ADSL | English | Asymetric digital subscriber line | Computing |
ADSL | French | Réseau de distribution numérique asymétrique | Post & Telecom |
ADSL | German | Einseitige Benutzergruppen-Verbindung | Electrical Engineering |
ADSL | Greek | ασύμμετρος ψηφιακός συνδρομητικός βρόχος | Electrical Engineering |
ADSL | Italian | Linea d'abbonato digitale asimmetrica | Post & Telecom |
ADSL | Portuguese | Linha digital assimétrica de assinante | Post & Telecom |
ADSL | Spanish | Bucle digital asimétrico de abonado | Electrical Engineering |
ADSL | Swedish | Asymmetrisk digital abonnentledning | Post & Telecom |
Source: compiled by the editor, based on several corpora (additional references). | |||
Crosswords: ADSL |
| Specialty definitions using "ADSL": Asymmetric Digital Subscriber Line ♦ Carrierless Amplitude/Phase Modulation ♦ Digital Subscriber Line ♦ Very high bit-rate Digital Subscriber Line. (references) |
| Non-English Usage: "ADSL" is also a word in the following language with English translations in parentheses. Portuguese (ADSL, asymmetric digital subscriber loop, asymmetrical digital subscriber loop). |
| Domain | Title | ||
Books |
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High Tech |
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Source: compiled by the editor from various references; see credits. | |||
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| "ADSL Splitter 1" by Gary McCord Commentary: "ADSL Splitter cable with Phone and ADSL Socket." |
Source: photographs selected by the editor, with permission from the photographers. |
| Subject | Topic | Quote |
Business | ADSL is fast, digital data transmission, using network lines that already exist. (references) | |
The use of expensive ISDN and ADSL lines is the only way to offer sufficient bandwidth to transmit moving images. (references) | ||
Of these, ca. 150,00 are ISDN connections and there were approximately 40,000 broadband subscriptions via ADSL, cable television or other means. (references) | ||
Economic History | Norway | The terrestrial network is currently being upgraded to ADSL. (references) |
Australia | Telstra has recently introduced ADSL technology to the major Australian cities. (references) | |
Saudi Arabia | STC is presently evaluating multiple technologies for Internet access like V.90/k-Flex, ISDN and ADSL. (references) | |
Source: compiled by the editor from ICON Group International, Inc.; see credits. | ||
| The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com. |
| Expression | Frequency per Day | Expression | Frequency per Day |
adsl | 2,177 | adsl tweak | 19 |
adsl modem | 290 | adsl splitters | 19 |
adsl router | 101 | connexion adsl | 18 |
adsl hosting web | 91 | adsl filter | 18 |
adsl speed test | 76 | internet adsl | 18 |
adsl provider | 53 | adsl booster | 18 |
adsl telus | 47 | adsl internet access | 18 |
adsl speed | 46 | adsl satellite | 17 |
adsl autoconnect | 41 | offres adsl | 17 |
adsl test | 41 | adsl driver modem | 17 |
adsl broadband | 32 | wireless adsl | 16 |
adsl linux | 29 | adsl connexion optimisation | 16 |
access adsl bizzonweb internet | 28 | adsl ethernet modem | 16 |
adsl modem router | 27 | offre adsl | 15 |
adsl uk | 27 | adsl australia | 14 |
couverture adsl | 24 | adsl es que | 14 |
adsl alice | 24 | alcatel adsl modem | 13 |
fax adsl | 23 | adsl services | 13 |
adsl splitter | 22 | adsl high speed internet access | 13 |
free adsl | 21 | adsl wanadoo | 13 |
adsl firewall | 13 | ||
| Source: compiled by the editor from various references; see credits. | |||
| Language | Translations for "ADSL"; alternative meanings/domain in parentheses. | |
Chinese | 非對稱式數據用戶線 (Asymmetrical Digital Subscriber Line). (various references) | |
Danish | asymmetrisk digitalt abonnentkredsløb (asymmetric digital subscriber loop), asymmetrical digital subscriber loop (asymmetrical digital subscriber loop), ADSL (asymmetric digital subscriber loop, asymmetrical digital subscriber loop). (various references) | |
Dutch | assymmetric digital subscriber loop (asymmetrical digital subscriber loop), ADSL (asymmetric digital subscriber loop, asymmetrical digital subscriber loop). (various references) | |
Finnish | ADSL-liittymä (asymmetric digital subscriber loop), epäsymmetrinen digitaalinen tilaajasilmukka (asymmetrical digital subscriber loop), epäsymmetrinen digitaalinen liittymä (asymmetric digital subscriber loop). (various references) | |
French | ADSL, réseau de raccordement numérique asymétrique, réseau de distribution numérique asymétrique, ligne numérique à paire asymétrique, ligne asymétrique d'abonné numérique, liaison numérique à débit asymétrique. (various references) | |
German | asymmetrischer digitaler Teilnehmeranschluss (asymmetric digital subscriber loop), Asymmetrical Digital Subscriber-Line (asymmetrical digital subscriber loop), ADSL (asymmetric digital subscriber loop, asymmetrical digital subscriber loop), einseitige Benutzergruppen-Verbindung (asymmetrical digital subscriber loop). (various references) | |
Greek | ADSL (asymmetrical digital subscriber loop). (various references) | |
Italian | Adsl (asymetric digital subscriber line, asymetric digital subscriber loop, asymmetric digital subscriber loop), linea d'abbonato digitale asimmetrica (asymmetric digital subscriber loop). (various references) | |
Pig Latin | adslay.(various references) | |
Portuguese | ADSL (asymmetric digital subscriber loop, asymmetrical digital subscriber loop), linha digital assimétrica de assinante (asymmetric digital subscriber loop), linha de assinante digital assimétrica (asymmetric digital subscriber loop, asymmetrical digital subscriber loop). (various references) | |
Spanish | ADSL (asymmetric digital subscriber loop, asymmetrical digital subscriber loop), línea digital asimétrica de abonado (asymmetrical digital subscriber loop), bucle digital asimétrico de abonado (asymmetrical digital subscriber loop), bucle de abonado asimétrico digital (asymmetric digital subscriber loop). (various references) | |
Swedish | asymmetrisk digital abonnentledning (asymmetric digital subscriber loop), ADSL (asymmetric digital subscriber loop). (various references) | |
| Source: compiled by the editor from various translation references. | ||
Scrabble® Enable2K-Verified Anagrams | |
Direct Anagrams: dals, lads. | |
| Words within the letters "a-d-l-s" | |
-1 letter: ads, als, dal, lad, las, sad, sal. | |
-2 letters: ad, al, as, la. | |
| Words containing the letters "a-d-l-s" | |
+1 letter: balds, clads, dahls, dales, deals, dhals, dials, duals, glads, lades, lands, lards, lased, lauds, leads, loads, sadly, salad, scald, skald. | |
+2 letters: addles, adults, aholds, aisled, alands, alcids, alders, aldols, aldose, alkyds, allods, almuds, blades, caulds, clades, dalasi, dalles, damsel, deasil, decals, delays, deltas, desalt, dismal, distal, doblas, dolmas, dorsal, dossal, drails, drawls, dulias, elands, faulds, glades, glands, halids, ideals, iliads, island, ladens, laders, ladies, ladles, lairds, lameds, lapsed, lashed, lasted, leased, liards, lidars, medals, naleds, padles, pedals, plaids, pleads, saddle, sailed, salads, salpid, salted, salved, sandal, scalds, scaled, sealed, sendal, shaled, sialid, skalds, slaked, slated, slaved, slayed, soland, soldan, staled, suldan, wealds, woalds. | |
| Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro. | |
| 1. Definition 2. Crosswords 3. Usage: Commercial 4. Images: Digital Art | 5. Quotations: Non-fiction 6. Expressions: Internet 7. Translations: Modern 8. Abbreviations | 9. Acronyms 10. Anagrams 11. Bibliography |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
