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The Suppliers section seems to be very short. I will be adding more Suppliers of ADSL/DSL services. Ishmael Rufus 16:18, 1 June 2007 (UTC)
There is an ISP by region page, if I get my data into a decent enough format up on www.adslgeek.com/isps, I should be able to donate a bucket load of data of ISP names by country - does anyone know the best method to do a bulk import of a lot of data? Adslgeek ( talk) 10:59, 25 July 2012 (UTC)
Is this better than DSL? What abuot cable? Whats the difference? Is it big or small?
That is not true. The theoretical maximum for G.992.1 for example is 13Mbps (224 downstream carriers * 15bit/carrier * 4kHz symbol frequency). --
69.105.224.209
Can someone elucidate DSLAM? I suppose it's DSL access apparatus, but abbreviations should be defined before use.
I understand that "Annex A" is for ADSL over analog lines while "Annex B" is for ISDN lines. Could someone enter this into the article with some info on how likely you are to need one or the other? Or other compatibilities or non-compatibilites to watch out for? Thanks. ---Ransom/CG
The spectrum breakdown is not entirely accurate in this article. CAP did allocate spectrum the way that the diagram indicates it, but DMT doesn't - it defines 247 (from memory - this figure might be a bit out) subchannels, each of which can be either upstream or downstream (dynamically). -- DaveSymonds 06:11, 21 September 2005 (UTC)
Yep, just looked it up: DMT splits the channel into 247 subchannels, each 4kHz wide. This is the standard way it's done now. -- DaveSymonds 06:15, 21 September 2005 (UTC) could someone explain to me exactly what dsl is used for im only 13 —Preceding unsigned comment added by 75.148.75.45 ( talk) 13:41, 27 September 2010 (UTC)
Out of interest, how does ADSL affect faxes? can you send or receive a fax on an ADSL line? - Ta bu shi da yu 05:34, 14 January 2006 (UTC)
ADSL is a syncronous protocol at the lowest data layer. Amusingly enough, it runs ATM (async transfer mode) on top of this layer, but it still used syncronised clocks at the sending and receiving end.
"Upstream rates start at 64 kbit/s and typically reach 256 kbit/s but can go as high as 1024 kbit/s." Is this also true for ADSL2 and ADSL2+? Or do they allow higher upstream rates? -- ozzmosis 10:26, 26 February 2006 (UTC)
The site only mentions the word "upload" once, maybe more information should be provided about uploading on ADSL, the uploading speed, and if uploading is affected by downloading. etc.-- 82.152.138.225 01:29, 8 March 2006 (UTC)
I thought I should point out that in Japan, download speeds for ADSL go as high as 47Mbps, and upload speeds up to 5Mbps. Without the proper technical background, I wouldn't want to alter this article, but I thought it might be useful info to add. For evidence of this see the NTT page, in English, on this: http://www.ntt-east.co.jp/product_e/05/2.html
This is not correct - in japan "adsl2++" is used , which extends the adsl spectrum to 3.75MHz, thus roughly doubling the downstream rate to 50Mbps.
5 Mbps upstream is with triple upstream - the upstream band is three times the US bandwidth of regular adsl. ~~===
I was wondering, if its approriate to mention that the shift from ATM backbone networks to Ethernet is also because of the future possibilities of using the same backbone network for other services like POTS or mobile phone networks?
..."or lower signal to noise (SNR)ratios"... Shouldn't this be lower Signal to Noise Ratios(SNR)? Cruxit 15:59, 14 June 2006 (UTC)
CarlosRibeiro 17:23, 21 October 2006 (UTC). I've dropped a note at the DSL history. I moved some notes on DSL installation that applied specifically to ADSL here. It refers to some history on the usage of splitters, that is not longer absolutely required but is still of interest, both historically and also to understand some practical aspects of the technology.
Hello
Is it correct to describe it as a digital technology since it modulates analogue carriers?
Thanks
I.I.A —The preceding unsigned comment was added by 195.130.120.24 ( talk) 09:03, 21 December 2006 (UTC).
The page here states the download speed is 28mbit, but the [[ITU G.992.5 Annex M] page says 24mbit... which is it? 125.236.153.184 09:05, 31 January 2007 (UTC)
Reading [1] I think it means this article is incorrectly capitalised, while Digital subscriber line is correctly titled. Does anyone agree that only the first word should be capitalized? Disagree? Think both styles are correct for their respective article? Jim.henderson 20:29, 19 March 2007 (UTC)
My USR router specs says that with S=1/2, it can do 12Mbps, up from 8. What does S=1/2 mean and how does it extend the download speed? Any info appreciated, cheers! 84.9.32.226 14:47, 25 June 2007 (UTC)
Feel free to add an ADSL column to the OFDM#OFDM system comparison table. Mange01 11:46, 17 July 2007 (UTC)
The discrete multitone system is basically Orthogonal Frequency Division Multiplexing (OFDM like DMT), with Quadrature Amplitude Modulation(QAM) on each sub-frequency. It may be as well to draw comparisons between the ADSL, VDSL, 802.11n and LTE 4G system modulation scheme as they have significant similarities. (In principle, the same).
Spectral efficiency is also an interesting subject as it opens the discussion to potential future improvements. Spectral efficiency can be expressed in bits/second/Hertz. With ADSL 2060KHz downstream bandwidth and a link of 24Mbit, this gives perhaps 12-14 bits per second per hertz accounting for FEC and control information. Suggesting QAM16384 as the coding scheme ona clear line. This is amongst the densest coding schemes in terms of b/s/hz.
Infinity, or VDSL2 brings the DSLAM closer to the customer, squeezing a little more from the coding. Perhaps another bit, but increases the bandwidth - top end frequency is higher. Nick Hill ( talk) 11:58, 29 March 2013 (UTC)
I came to this page to find out when ADSL was invented and rolled out. If someone knows, can they add it to the article? It would also be good to know who invented it. exterminator 11:06, 8 August 2007 (UTC)
I came here hoping to find a definitive answer, because Verizon's claims make no sense ("768 kbit/s DSL is 21 times faster than 56k dialup"). 768/56 == 13 which is nowhere near Verizon's claim. (It's even less when you consider 56K modems use compression to increase effective thoughput to ~150 kbps).) I'd like to find an actual study that's not biased by salesmanship. - Theaveng 17:37, 14 September 2007 (UTC)
Typical marketing flim-flam, probably. Remember that the max tech speed of this segment of the SYSTEM that you are using is only one factor in the response you experience. Your computer is a factor. Latencies anywhere along the way are a factor, that remains no matter how fast the peak speeds. As a practical matter, you can hope that DSL will be about ten times faster than dial-up, in real life. - 69.87.200.195 ( talk) 11:17, 24 March 2008 (UTC)
My dialup modem uses V.44 to compress text 6-to-1 (effective throughput of 300 kbit/s) and executables like flash programs 3-to-1 (effective throughput of 150 kbit/s). Does DSL use a similar technology to squash data on the fly? - Theaveng ( talk) 18:30, 20 November 2007 (UTC)
I think this part is about how it is done in the USA? This can be very different depending on local telephone installations in other parts of the world.
Example: ADSL is very in wide use in Germany now and local installation is usually done by the customer, but I have never heard of a microfilter. When you order ADSL you get a spitter from your provider and you install it yourself by pluging it into the telephone jack. The splitter is the only device directly connected to the public network. The splitter itself has two outputs, one for a DSL modem and one for a telephone or an ISDN network termination device. Since the combination of ADSL+ISDN is very common in Germany , there are combined spliiter/termination boxes (called "NTSplit" or something), sometimes there is even a small ISDN PBX inside that box.
I think microfilters make sense if you have multiple telefone jacks that are simply wired parallel. This kind of installation is not even allowed here. If you want more than one telefone you use a small PBX (or ISDN devices connectes to a S0 bus) with the ADSL splitter in front.
Christian —Preceding unsigned comment added by 80.133.139.40 ( talk) 15:51, 15 January 2008 (UTC)
Where in the OSI model do (A)DSL and ADSL+ fit? In the link layer? —Preceding unsigned comment added by 194.251.240.114 ( talk) 12:42, 7 February 2008 (UTC)
It is great to have all this tech info about the range of possible speeds. But it would be good to also have a table of the most common marketed speeds. In the US 2008 at the low end for Verizon that is 768 Kbps / 128 Kbps. It would be interesting to see a table of the most common low-end DSL speeds current around the world, and the average price. - 69.87.200.195 ( talk) 11:11, 24 March 2008 (UTC)
The footnote for Annex L seems to be ineditable. I was one of the contributors to that bit of text, and I think it should probably be changed a bit by now, but that doesn't seem to be possible anymore, or am I missing something? KryzMasta ( talk) 21:55, 8 April 2008 (UTC)
What is the source for the downstream/upstream bitrates of the various modulations and annexes? The G.99* documents don't specify a theoretical maximum that I can see. Kisch ( talk) 11:29, 20 November 2008 (UTC)
On 3 December 2008
Mikeblas tagged this article as possibly containing original research or unverified claims. I have searched and cannot find any evidence for this, and Mikeblas has not explained his reasons on this talk page. Can anyone indicate where the possible original research is?
On the same date Mikeblas also tagged the article as citing no references or sources. Certainly it would be good to have sources cited, but is this the reason for the original research tag too?
The following is quoted from the
Wikipedia Verifiability policy:
It is worth noting that this refers quite explicitly to "material challenged or likely to be challenged", and does not support the view which seems to be held by many Wikipedia editors that articles must always cite references, even if the information given is quite uncontroversial.
JamesBWatson (
talk)
14:45, 9 December 2008 (UTC)
(1) After almost 2 months nobody has supported the original research/unverified claims tag, so I have removed it.
(2) Some references to sources are now included, so I have removed the unreferenced tag.
(3) On 28 January 2009 an anonymous editor operating from IP address 87.78.35.109 tagged the article with "The external links in this article may not follow Wikipedia's content policies or guidelines." Having looked at the links in question I agree, and I have removed a few links which I regard as particularly marginal. However, it seems to me that several more of the links given might not be justifiable under the terms of Wikipedia's external links policy, in particular "...one should avoid: Any site that does not provide a unique resource beyond what the article would contain if it became a Featured article." Does anyone wish to either defend any of the remaining links or propose removing them? JamesBWatson ( talk) 12:55, 4 February 2009 (UTC)
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 voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call.[1] A splitter - or microfilter - allows a single telephone connection to be used for both ADSL service and voice calls at the same time. Because phone lines vary in quality and were not originally engineered with DSL in mind, it can generally only be used over short distances, typically less than 4km[2].
At the telephone exchange the line generally terminates at a DSLAM where another frequency splitter separates the voice band signal for the conventional phone network. Data carried by the ADSL is typically routed over the telephone company's data network and eventually reaches a conventional internet network. In the UK under British Telecom the data network in question is its ATM network which in turn sends it to its IP network IP Colossus. —Preceding unsigned comment added by 125.21.240.2 ( talk) 11:29, 14 February 2009 (UTC)
I have noticed that my ADSL connection slows down during a thunderstorm. I did some searching using the terms "rain slow dsl" and I discovered that there have been many cases of people complaining (on message boards)of loosing their ADSL connections due to rain and thunderstorms. I can not find any solid resources that would warrant an article edit. Anyone know of any good resources on this issue? Dreammaker182 03:52, 13 April 2009 (UTC)
No I don't. However, I should think the thunder would be more likely to be the cause than the rain. JamesBWatson ( talk) 10:25, 15 April 2009 (UTC)
Any signal on these wires suffers in storms, mostly due to two causes:
In the case of analog signals, we hear the click, buzz or other noise. For digital signals a packet is corrupted and the receiving modem requests retransmissions, possibly many retransmissions, possibly at lower speed, until an uncorrupted version arrives.
I realise that there is a paragraph above where somebody asked if this technology was digital or analogue - and it was never answered. I came to the ADSL page to find that out. It turns out that the Wiki page on ADSL does not answer this. I'm pretty sure that ADSL is NOT digital - it is just analogue way above the 20kHz that humans can hear. Can somebody that knows this technology STATE THAT in the first couple of sentences of this Wikipedia entry???? If not, I am going to have to do that in the next week or so - I would prefer not to do that - I am not an expert on this technology. But I think it is not a good Wiki article if you go to ADSL and never read that "it is NOT digital - it is an ANALOGUE technology". Please help me out here. Thanks. —Preceding unsigned comment added by 86.143.154.57 ( talk) 05:13, 8 May 2009 (UTC)
ok, but if I am allowed to ask, for the shake of conversation: plain old modems up to V.90 would also be referred as digital technology? why do we refer to dial-up modems as analog and to ISDN as digital? based on the same assumption I would still refer to ADSL as analog (versus ISDN as digital) (since ADSL also uses QAM as the last dial up modems did) isn't the signal that "travels" in the wire analog for ADSL and digital for ISDN? 195.130.120.24 ( talk) 10:07, 18 September 2010 (UTC)
Suggestion: A section criticisms of ADSL be added
Rationale: I have plenty of field experience of ADSL and have experienced problems personally. Where the local loop has few ADSL subscribers, the quality and reliability of service tends to be excellent. I have observed that over time, the quality of service on many lines has degraded.
I imagine this is caused by crosstalk. Crosstalk is a well known and well defined property of wires in close proximity. The local loop was designed with 4Khz voice bands in mind, and with relatively few lines active at once. If the frequency is pushed from 4Khz to 138Khz (lowest downstream), the level of crosstalk for those high frequency transmissions will be orders of magnitude greater.
Local loop wiring will have a pair of wires for each subscriber, in a bundle, laid under the pavement from the local end-of-street box to the exchange. That bundle may contain hundreds of individual pairs over perhaps many miles. ADSL tends to become a victim of it's success; as more subscribers opt for ADSL, the proportion of those pairs which carry HF ADSL frequencies increases leading to the noise induced into each wire in that bundle increasing. Once saturation is reached, a new subscriber will result in an existing subscriber, further from the exchange, experience the ADSL HF noise on their line increase beyond the maximum threshold. In effect, there is a maximum number of ADSL signals which can be carried by a bundle. Those further away from the exchange will be knocked off ADSL first. A local loop bundle of wires will generally have an ADSL carrying capacity of far less than the number of phone lines carried.
The criticism so far is that of the local loop infrastructure when it applies to the ADSL coding scheme. This criticism could extend to the ADSL coding scheme as follows:
1) Lines which can carry voice calls will often not sync an ADSL signal at all; if ADSL were more flexible in choosing upstream and downstream frequency bands, ADSL would presumably sync on very poor lines by establishing both an upstream and downstream path close to audio frequencies. If not providing broadband, at least an always-on internet service.
2) Related to 1) above, ADSL tends to fail abruptly rather than gracefully. Once noise has reduced the sync to 700Kbit, a slight increase in noise has, in my experience, broken the connection completely rather than the preferred behaviour of the system continually lowering the data rate. A better design would exploit any usable clear frequency bands the line has, to maintain some sort of bi-directional connection. Both attenuation and crosstalk-induced noise will tend to be higher at higher frequencies.
3) ADSL always noisy: Given the issues so far seem not to have been fully factored in the ADSL system design, it may be that ADSL generates a lot of HF noise on lines even when data is not being communicated. If the system tended towards minimum hf signal generation, the local loop capacity may not be limited by number of subscribers, but by data volume carried, aggregated across subscribers served by the bundle of wires. Given most ADSL modems are not transferring data at max rate 24/7, a 'quiet' ADSL system may lead to a much higher local loop capacity.
These problems could potentially be solved by re-defining the ADSL specification, and perhaps minor (if any) equipment hardware modification, to have a more flexible frequency choice and for ADSL to make less noise when not actively transferring data. Overall, the best approach would be for telecoms companies to change the topology of the local loop to terminate a line closer to the home or premises.( Fiber_to_the_x). Nick R Hill ( talk) 11:04, 5 July 2009 (UTC)
"CJ Currie Overview
CJ can run at 3MPH over a distance of 1KM, in terms of fibre hes a fat bastered" —Preceding unsigned comment added by 41.132.178.11 ( talk) 11:25, 21 April 2010 (UTC)
could u explain to me exactly what dsl is used for im only 13 2010 september,27 thx —Preceding
unsigned comment added by
75.148.75.45 (
talk)
13:50, 27 September 2010 (UTC)
I found it impossible to decipher this text:
"The distance from the telephone exchange and the characteristics of the cable mean that some frequencies may not propagate well, and noise on the copper wire, interference from AM radio stations and local interference and electrical noise at the customer end mean that relatively high levels of noise are present at some frequencies both effects the signal-to-noise ratio in some bins (at some frequencies) may be good or completely inadequate."
This part reads like a complete sentence:
"The distance from the telephone exchange and the characteristics of the cable mean that some frequencies may not propagate well, and noise on the copper wire, interference from AM radio stations and local interference and electrical noise at the customer end mean that relatively high levels of noise are present at some frequencies"
... but then there is this tagged on the end?
" both effects the signal-to-noise ratio in some bins (at some frequencies) may be good or completely inadequate."
Perhaps this could be re-worded or split into two or more sentences for better expression of the intended meaning.
Thanks. -- 86.186.216.130 ( talk) 09:13, 30 September 2010 (UTC)
The result of the move request was: page moved. Vegaswikian ( talk) 02:31, 20 September 2011 (UTC)
Asymmetric Digital Subscriber Line →
Asymmetric digital subscriber line –
It's just a line, yes? Not a proprietary term or a title. No one "owns" it. Generic and used worldwide as a concept, technique, or technology by companies all over the place. Per WP:CAPS and WP:TITLE: this is a generic, common term, not a propriety or commerical term, the article title should be downcased. WP:MOS says that a compound item should not be upper-cased just because it is abbreviated with caps. Tony (talk) 02:18, 13 September 2011 (UTC)
So if I understand the article correctly, the DSL signal and the phone signal use the same wires in e.g. an RJ-12 cable? 75.121.7.160 ( talk) 03:09, 31 May 2012 (UTC)
Additions in this appear purely reflective based on opinions formed from personal knowledge. Unlike hard facts, soft theories are like philosophy and are subject to interpretation and the editor provided no attribution to reliable sources to support his theory. It is a free write up off his mind and we're not a political banter box. Cantaloupe2 ( talk) 11:34, 19 August 2013 (UTC)
Surely, users send URLs to websites and email. — Preceding unsigned comment added by 81.151.133.212 ( talk) 11:34, 10 October 2016 (UTC)
The result of the move request was: moved per request. Favonian ( talk) 20:50, 19 November 2022 (UTC)
Asymmetric digital subscriber line → ADSL – Per WP:COMMONNAME and MOS:ACROTITLE. PhotographyEdits ( talk) 11:04, 12 November 2022 (UTC)
This is the
talk page for discussing improvements to the
ADSL article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
This article is rated C-class on Wikipedia's
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The Suppliers section seems to be very short. I will be adding more Suppliers of ADSL/DSL services. Ishmael Rufus 16:18, 1 June 2007 (UTC)
There is an ISP by region page, if I get my data into a decent enough format up on www.adslgeek.com/isps, I should be able to donate a bucket load of data of ISP names by country - does anyone know the best method to do a bulk import of a lot of data? Adslgeek ( talk) 10:59, 25 July 2012 (UTC)
Is this better than DSL? What abuot cable? Whats the difference? Is it big or small?
That is not true. The theoretical maximum for G.992.1 for example is 13Mbps (224 downstream carriers * 15bit/carrier * 4kHz symbol frequency). --
69.105.224.209
Can someone elucidate DSLAM? I suppose it's DSL access apparatus, but abbreviations should be defined before use.
I understand that "Annex A" is for ADSL over analog lines while "Annex B" is for ISDN lines. Could someone enter this into the article with some info on how likely you are to need one or the other? Or other compatibilities or non-compatibilites to watch out for? Thanks. ---Ransom/CG
The spectrum breakdown is not entirely accurate in this article. CAP did allocate spectrum the way that the diagram indicates it, but DMT doesn't - it defines 247 (from memory - this figure might be a bit out) subchannels, each of which can be either upstream or downstream (dynamically). -- DaveSymonds 06:11, 21 September 2005 (UTC)
Yep, just looked it up: DMT splits the channel into 247 subchannels, each 4kHz wide. This is the standard way it's done now. -- DaveSymonds 06:15, 21 September 2005 (UTC) could someone explain to me exactly what dsl is used for im only 13 —Preceding unsigned comment added by 75.148.75.45 ( talk) 13:41, 27 September 2010 (UTC)
Out of interest, how does ADSL affect faxes? can you send or receive a fax on an ADSL line? - Ta bu shi da yu 05:34, 14 January 2006 (UTC)
ADSL is a syncronous protocol at the lowest data layer. Amusingly enough, it runs ATM (async transfer mode) on top of this layer, but it still used syncronised clocks at the sending and receiving end.
"Upstream rates start at 64 kbit/s and typically reach 256 kbit/s but can go as high as 1024 kbit/s." Is this also true for ADSL2 and ADSL2+? Or do they allow higher upstream rates? -- ozzmosis 10:26, 26 February 2006 (UTC)
The site only mentions the word "upload" once, maybe more information should be provided about uploading on ADSL, the uploading speed, and if uploading is affected by downloading. etc.-- 82.152.138.225 01:29, 8 March 2006 (UTC)
I thought I should point out that in Japan, download speeds for ADSL go as high as 47Mbps, and upload speeds up to 5Mbps. Without the proper technical background, I wouldn't want to alter this article, but I thought it might be useful info to add. For evidence of this see the NTT page, in English, on this: http://www.ntt-east.co.jp/product_e/05/2.html
This is not correct - in japan "adsl2++" is used , which extends the adsl spectrum to 3.75MHz, thus roughly doubling the downstream rate to 50Mbps.
5 Mbps upstream is with triple upstream - the upstream band is three times the US bandwidth of regular adsl. ~~===
I was wondering, if its approriate to mention that the shift from ATM backbone networks to Ethernet is also because of the future possibilities of using the same backbone network for other services like POTS or mobile phone networks?
..."or lower signal to noise (SNR)ratios"... Shouldn't this be lower Signal to Noise Ratios(SNR)? Cruxit 15:59, 14 June 2006 (UTC)
CarlosRibeiro 17:23, 21 October 2006 (UTC). I've dropped a note at the DSL history. I moved some notes on DSL installation that applied specifically to ADSL here. It refers to some history on the usage of splitters, that is not longer absolutely required but is still of interest, both historically and also to understand some practical aspects of the technology.
Hello
Is it correct to describe it as a digital technology since it modulates analogue carriers?
Thanks
I.I.A —The preceding unsigned comment was added by 195.130.120.24 ( talk) 09:03, 21 December 2006 (UTC).
The page here states the download speed is 28mbit, but the [[ITU G.992.5 Annex M] page says 24mbit... which is it? 125.236.153.184 09:05, 31 January 2007 (UTC)
Reading [1] I think it means this article is incorrectly capitalised, while Digital subscriber line is correctly titled. Does anyone agree that only the first word should be capitalized? Disagree? Think both styles are correct for their respective article? Jim.henderson 20:29, 19 March 2007 (UTC)
My USR router specs says that with S=1/2, it can do 12Mbps, up from 8. What does S=1/2 mean and how does it extend the download speed? Any info appreciated, cheers! 84.9.32.226 14:47, 25 June 2007 (UTC)
Feel free to add an ADSL column to the OFDM#OFDM system comparison table. Mange01 11:46, 17 July 2007 (UTC)
The discrete multitone system is basically Orthogonal Frequency Division Multiplexing (OFDM like DMT), with Quadrature Amplitude Modulation(QAM) on each sub-frequency. It may be as well to draw comparisons between the ADSL, VDSL, 802.11n and LTE 4G system modulation scheme as they have significant similarities. (In principle, the same).
Spectral efficiency is also an interesting subject as it opens the discussion to potential future improvements. Spectral efficiency can be expressed in bits/second/Hertz. With ADSL 2060KHz downstream bandwidth and a link of 24Mbit, this gives perhaps 12-14 bits per second per hertz accounting for FEC and control information. Suggesting QAM16384 as the coding scheme ona clear line. This is amongst the densest coding schemes in terms of b/s/hz.
Infinity, or VDSL2 brings the DSLAM closer to the customer, squeezing a little more from the coding. Perhaps another bit, but increases the bandwidth - top end frequency is higher. Nick Hill ( talk) 11:58, 29 March 2013 (UTC)
I came to this page to find out when ADSL was invented and rolled out. If someone knows, can they add it to the article? It would also be good to know who invented it. exterminator 11:06, 8 August 2007 (UTC)
I came here hoping to find a definitive answer, because Verizon's claims make no sense ("768 kbit/s DSL is 21 times faster than 56k dialup"). 768/56 == 13 which is nowhere near Verizon's claim. (It's even less when you consider 56K modems use compression to increase effective thoughput to ~150 kbps).) I'd like to find an actual study that's not biased by salesmanship. - Theaveng 17:37, 14 September 2007 (UTC)
Typical marketing flim-flam, probably. Remember that the max tech speed of this segment of the SYSTEM that you are using is only one factor in the response you experience. Your computer is a factor. Latencies anywhere along the way are a factor, that remains no matter how fast the peak speeds. As a practical matter, you can hope that DSL will be about ten times faster than dial-up, in real life. - 69.87.200.195 ( talk) 11:17, 24 March 2008 (UTC)
My dialup modem uses V.44 to compress text 6-to-1 (effective throughput of 300 kbit/s) and executables like flash programs 3-to-1 (effective throughput of 150 kbit/s). Does DSL use a similar technology to squash data on the fly? - Theaveng ( talk) 18:30, 20 November 2007 (UTC)
I think this part is about how it is done in the USA? This can be very different depending on local telephone installations in other parts of the world.
Example: ADSL is very in wide use in Germany now and local installation is usually done by the customer, but I have never heard of a microfilter. When you order ADSL you get a spitter from your provider and you install it yourself by pluging it into the telephone jack. The splitter is the only device directly connected to the public network. The splitter itself has two outputs, one for a DSL modem and one for a telephone or an ISDN network termination device. Since the combination of ADSL+ISDN is very common in Germany , there are combined spliiter/termination boxes (called "NTSplit" or something), sometimes there is even a small ISDN PBX inside that box.
I think microfilters make sense if you have multiple telefone jacks that are simply wired parallel. This kind of installation is not even allowed here. If you want more than one telefone you use a small PBX (or ISDN devices connectes to a S0 bus) with the ADSL splitter in front.
Christian —Preceding unsigned comment added by 80.133.139.40 ( talk) 15:51, 15 January 2008 (UTC)
Where in the OSI model do (A)DSL and ADSL+ fit? In the link layer? —Preceding unsigned comment added by 194.251.240.114 ( talk) 12:42, 7 February 2008 (UTC)
It is great to have all this tech info about the range of possible speeds. But it would be good to also have a table of the most common marketed speeds. In the US 2008 at the low end for Verizon that is 768 Kbps / 128 Kbps. It would be interesting to see a table of the most common low-end DSL speeds current around the world, and the average price. - 69.87.200.195 ( talk) 11:11, 24 March 2008 (UTC)
The footnote for Annex L seems to be ineditable. I was one of the contributors to that bit of text, and I think it should probably be changed a bit by now, but that doesn't seem to be possible anymore, or am I missing something? KryzMasta ( talk) 21:55, 8 April 2008 (UTC)
What is the source for the downstream/upstream bitrates of the various modulations and annexes? The G.99* documents don't specify a theoretical maximum that I can see. Kisch ( talk) 11:29, 20 November 2008 (UTC)
On 3 December 2008
Mikeblas tagged this article as possibly containing original research or unverified claims. I have searched and cannot find any evidence for this, and Mikeblas has not explained his reasons on this talk page. Can anyone indicate where the possible original research is?
On the same date Mikeblas also tagged the article as citing no references or sources. Certainly it would be good to have sources cited, but is this the reason for the original research tag too?
The following is quoted from the
Wikipedia Verifiability policy:
It is worth noting that this refers quite explicitly to "material challenged or likely to be challenged", and does not support the view which seems to be held by many Wikipedia editors that articles must always cite references, even if the information given is quite uncontroversial.
JamesBWatson (
talk)
14:45, 9 December 2008 (UTC)
(1) After almost 2 months nobody has supported the original research/unverified claims tag, so I have removed it.
(2) Some references to sources are now included, so I have removed the unreferenced tag.
(3) On 28 January 2009 an anonymous editor operating from IP address 87.78.35.109 tagged the article with "The external links in this article may not follow Wikipedia's content policies or guidelines." Having looked at the links in question I agree, and I have removed a few links which I regard as particularly marginal. However, it seems to me that several more of the links given might not be justifiable under the terms of Wikipedia's external links policy, in particular "...one should avoid: Any site that does not provide a unique resource beyond what the article would contain if it became a Featured article." Does anyone wish to either defend any of the remaining links or propose removing them? JamesBWatson ( talk) 12:55, 4 February 2009 (UTC)
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 voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call.[1] A splitter - or microfilter - allows a single telephone connection to be used for both ADSL service and voice calls at the same time. Because phone lines vary in quality and were not originally engineered with DSL in mind, it can generally only be used over short distances, typically less than 4km[2].
At the telephone exchange the line generally terminates at a DSLAM where another frequency splitter separates the voice band signal for the conventional phone network. Data carried by the ADSL is typically routed over the telephone company's data network and eventually reaches a conventional internet network. In the UK under British Telecom the data network in question is its ATM network which in turn sends it to its IP network IP Colossus. —Preceding unsigned comment added by 125.21.240.2 ( talk) 11:29, 14 February 2009 (UTC)
I have noticed that my ADSL connection slows down during a thunderstorm. I did some searching using the terms "rain slow dsl" and I discovered that there have been many cases of people complaining (on message boards)of loosing their ADSL connections due to rain and thunderstorms. I can not find any solid resources that would warrant an article edit. Anyone know of any good resources on this issue? Dreammaker182 03:52, 13 April 2009 (UTC)
No I don't. However, I should think the thunder would be more likely to be the cause than the rain. JamesBWatson ( talk) 10:25, 15 April 2009 (UTC)
Any signal on these wires suffers in storms, mostly due to two causes:
In the case of analog signals, we hear the click, buzz or other noise. For digital signals a packet is corrupted and the receiving modem requests retransmissions, possibly many retransmissions, possibly at lower speed, until an uncorrupted version arrives.
I realise that there is a paragraph above where somebody asked if this technology was digital or analogue - and it was never answered. I came to the ADSL page to find that out. It turns out that the Wiki page on ADSL does not answer this. I'm pretty sure that ADSL is NOT digital - it is just analogue way above the 20kHz that humans can hear. Can somebody that knows this technology STATE THAT in the first couple of sentences of this Wikipedia entry???? If not, I am going to have to do that in the next week or so - I would prefer not to do that - I am not an expert on this technology. But I think it is not a good Wiki article if you go to ADSL and never read that "it is NOT digital - it is an ANALOGUE technology". Please help me out here. Thanks. —Preceding unsigned comment added by 86.143.154.57 ( talk) 05:13, 8 May 2009 (UTC)
ok, but if I am allowed to ask, for the shake of conversation: plain old modems up to V.90 would also be referred as digital technology? why do we refer to dial-up modems as analog and to ISDN as digital? based on the same assumption I would still refer to ADSL as analog (versus ISDN as digital) (since ADSL also uses QAM as the last dial up modems did) isn't the signal that "travels" in the wire analog for ADSL and digital for ISDN? 195.130.120.24 ( talk) 10:07, 18 September 2010 (UTC)
Suggestion: A section criticisms of ADSL be added
Rationale: I have plenty of field experience of ADSL and have experienced problems personally. Where the local loop has few ADSL subscribers, the quality and reliability of service tends to be excellent. I have observed that over time, the quality of service on many lines has degraded.
I imagine this is caused by crosstalk. Crosstalk is a well known and well defined property of wires in close proximity. The local loop was designed with 4Khz voice bands in mind, and with relatively few lines active at once. If the frequency is pushed from 4Khz to 138Khz (lowest downstream), the level of crosstalk for those high frequency transmissions will be orders of magnitude greater.
Local loop wiring will have a pair of wires for each subscriber, in a bundle, laid under the pavement from the local end-of-street box to the exchange. That bundle may contain hundreds of individual pairs over perhaps many miles. ADSL tends to become a victim of it's success; as more subscribers opt for ADSL, the proportion of those pairs which carry HF ADSL frequencies increases leading to the noise induced into each wire in that bundle increasing. Once saturation is reached, a new subscriber will result in an existing subscriber, further from the exchange, experience the ADSL HF noise on their line increase beyond the maximum threshold. In effect, there is a maximum number of ADSL signals which can be carried by a bundle. Those further away from the exchange will be knocked off ADSL first. A local loop bundle of wires will generally have an ADSL carrying capacity of far less than the number of phone lines carried.
The criticism so far is that of the local loop infrastructure when it applies to the ADSL coding scheme. This criticism could extend to the ADSL coding scheme as follows:
1) Lines which can carry voice calls will often not sync an ADSL signal at all; if ADSL were more flexible in choosing upstream and downstream frequency bands, ADSL would presumably sync on very poor lines by establishing both an upstream and downstream path close to audio frequencies. If not providing broadband, at least an always-on internet service.
2) Related to 1) above, ADSL tends to fail abruptly rather than gracefully. Once noise has reduced the sync to 700Kbit, a slight increase in noise has, in my experience, broken the connection completely rather than the preferred behaviour of the system continually lowering the data rate. A better design would exploit any usable clear frequency bands the line has, to maintain some sort of bi-directional connection. Both attenuation and crosstalk-induced noise will tend to be higher at higher frequencies.
3) ADSL always noisy: Given the issues so far seem not to have been fully factored in the ADSL system design, it may be that ADSL generates a lot of HF noise on lines even when data is not being communicated. If the system tended towards minimum hf signal generation, the local loop capacity may not be limited by number of subscribers, but by data volume carried, aggregated across subscribers served by the bundle of wires. Given most ADSL modems are not transferring data at max rate 24/7, a 'quiet' ADSL system may lead to a much higher local loop capacity.
These problems could potentially be solved by re-defining the ADSL specification, and perhaps minor (if any) equipment hardware modification, to have a more flexible frequency choice and for ADSL to make less noise when not actively transferring data. Overall, the best approach would be for telecoms companies to change the topology of the local loop to terminate a line closer to the home or premises.( Fiber_to_the_x). Nick R Hill ( talk) 11:04, 5 July 2009 (UTC)
"CJ Currie Overview
CJ can run at 3MPH over a distance of 1KM, in terms of fibre hes a fat bastered" —Preceding unsigned comment added by 41.132.178.11 ( talk) 11:25, 21 April 2010 (UTC)
could u explain to me exactly what dsl is used for im only 13 2010 september,27 thx —Preceding
unsigned comment added by
75.148.75.45 (
talk)
13:50, 27 September 2010 (UTC)
I found it impossible to decipher this text:
"The distance from the telephone exchange and the characteristics of the cable mean that some frequencies may not propagate well, and noise on the copper wire, interference from AM radio stations and local interference and electrical noise at the customer end mean that relatively high levels of noise are present at some frequencies both effects the signal-to-noise ratio in some bins (at some frequencies) may be good or completely inadequate."
This part reads like a complete sentence:
"The distance from the telephone exchange and the characteristics of the cable mean that some frequencies may not propagate well, and noise on the copper wire, interference from AM radio stations and local interference and electrical noise at the customer end mean that relatively high levels of noise are present at some frequencies"
... but then there is this tagged on the end?
" both effects the signal-to-noise ratio in some bins (at some frequencies) may be good or completely inadequate."
Perhaps this could be re-worded or split into two or more sentences for better expression of the intended meaning.
Thanks. -- 86.186.216.130 ( talk) 09:13, 30 September 2010 (UTC)
The result of the move request was: page moved. Vegaswikian ( talk) 02:31, 20 September 2011 (UTC)
Asymmetric Digital Subscriber Line →
Asymmetric digital subscriber line –
It's just a line, yes? Not a proprietary term or a title. No one "owns" it. Generic and used worldwide as a concept, technique, or technology by companies all over the place. Per WP:CAPS and WP:TITLE: this is a generic, common term, not a propriety or commerical term, the article title should be downcased. WP:MOS says that a compound item should not be upper-cased just because it is abbreviated with caps. Tony (talk) 02:18, 13 September 2011 (UTC)
So if I understand the article correctly, the DSL signal and the phone signal use the same wires in e.g. an RJ-12 cable? 75.121.7.160 ( talk) 03:09, 31 May 2012 (UTC)
Additions in this appear purely reflective based on opinions formed from personal knowledge. Unlike hard facts, soft theories are like philosophy and are subject to interpretation and the editor provided no attribution to reliable sources to support his theory. It is a free write up off his mind and we're not a political banter box. Cantaloupe2 ( talk) 11:34, 19 August 2013 (UTC)
Surely, users send URLs to websites and email. — Preceding unsigned comment added by 81.151.133.212 ( talk) 11:34, 10 October 2016 (UTC)
The result of the move request was: moved per request. Favonian ( talk) 20:50, 19 November 2022 (UTC)
Asymmetric digital subscriber line → ADSL – Per WP:COMMONNAME and MOS:ACROTITLE. PhotographyEdits ( talk) 11:04, 12 November 2022 (UTC)