Talk:Digital subscriber line

I capitalized Ethernet. Ethernet is always capitalized. --imars 09:31, 22 Nov 2004 (UTC)

---

I cut this:

Some of the common "DSL Killers" are:

• Bridged taps
• Load coils
• "SLIC" boxes, or splitters, where copper capacity is increased by extending with multiple fibres. DSL can't travel over fibre, and most telephone companies choose not to offer fibre connections to residential customers.
• "DACS" boxes, where two baseband analog telephone lines are multiplexed over a single copper pair using ISDN-like technology to connect to the central office. Neither of the multiplexed lines is then usable for either DSL or ISDN service, as there is no metallic high-frequency path available. Where the central office connection is demultiplexed to analog connections, there is the added disadvantage that standard analog modem speeds are also reduced significantly.

As I'm not sure what its trying to say. You obviously need a continous copper line from CP to CO and I think this muddies the waters. Alex

I see that the titles Asymmetric Digital Subscriber Line, Integrated Services Digital Network, Asynchronous Transfer Mode, Asymmetric Digital Subscriber Line, and Digital Subscriber Line are all capitalized. These articles tend to have lots of incorrectly capitalized letters in the body of the article, and that makes me suspect that someone may have written them as capitals under the incorrect impression that the Wikipedia convention is to capitalize words in article titles? What is going on? Michael Hardy 21:23, 2 Aug 2004 (UTC)

dsl inventor

I am aware DSL technology started in Bell lab at around 1988. However, i can't see to find the guy behind the technology. A used google to try and look it up, but it looks like hundreds of people are claimimg dsl as their invention. This make it all the more important to find the real inventor and give credit to the right guy. I am aware that all inventions are progressive work and that Claude Shannon did most of the theoritical work, but then humans like personalizing achievement and hence the need of the guy who put things together and called it dsl. GITLIN, Richard claim to be one of them in this article [1] Anyone know the history behind this?

History

There should be more on the DSL History. Like how it was at one point intended to carry Video-On-Demand. linky

DSL history - sources?

The first paragraph on the DSL page makes some claims that I haven't heard elsewhere. Some sources are needed for it(news reports, historical studies, etc.). It's good writing, and interesting, but it needs to be sourced.

The paragraph: "Its origin dates back to 1988, when an engineer at Bell research lab deviced a way to carry digital signal over the unused frequency spectrum. This allows ordinary phone line to provide digital communication without blocking access to voice services. Bells management however were not enthusiastic about it as it was not as profitable as renting out a second line for those consumers who prefered to still have acess to the phone when dialing out. This however changed in the late 90s when cable companies started marketing broadband internet access. Realising that most consumers would prefer broadband over a second dial out line, Bell companies rushed out the DSL technology that they had been sitting on for the past decade as an attempt to slow broadband internet access uptake." - diff (Also posted on User talk:Wk muriithi) JesseW 19:48, 6 Apr 2005 (UTC)

wk muriithi replied on my talk page saying he got it from "Crafting and Executing strategy 14th edition by Arthur A. Thompson Jr.". If someone who has a copy could verify this, and add it as a footnote(use Wikipedia:Footnote3 style) that would be great. Thanks for replying, Wk! JesseW 05:34, 15 Apr 2005 (UTC)

DSL "modems"

I heard some claim that DSL modems aren't really modems. Is this just BS? - Omegatron 01:18, Apr 15, 2005 (UTC)

I'd say that's BS. The definition of a modem is something that takes data and modulates it onto an analog signal on one end and then demodulates it back to digital at the other end. What's called a DSL modem can be thought of as a whole bunch of dial-up modems working in parallel at different frequencies to get you a large pipe. I've just rewritten the "How it Works" section of the main article that explains it in some technical detail. --Blrfl Apr 17, 2005

I'd say it depends what you heard...these days most CP xDSL equipment is actuall a ROUTER, typically supporting NAT, and generally also a DHCP SERVER Xaosflux 05:42, 11 November 2005 (UTC)

Most widely used variety?

I wonder what variety of DSL is most commonly used? The only variety offered in my country is ADSL so I have no clue what is used in other countries. As I see it, ADSL is the most reliable variety, and hence the most common used. Can anyone comment on this? --Opiax 19:19, 25 Apr 2005 (UTC)

ADSL is by far the most common, but it's less an issue of reliability than one of giving the customers, most of whom receive far more than they send, high download speeds. With the exception of IDSL (which isn't really DSL; it's just a bonded pair of ISDN B channels), all of the flavors of DSL are pretty much the same from a technical standpoint. Two things differentiate them. First is the amount of spectrum above the baseband POTS signal. This is, effectively, a measure of the size of the pipe that carries all of your data in both directions. It's determined to a large extent by the basic technology in use (DSL, HDSL, VDSL) and the length and condition of the copper between you and the DSLAM. The second is whether the fractions devoted to the upstream and downstream channels are equal (for Symetric DSL or SDSL) or different (for Asymetric DSL or ADSL). As an example, my DSL line has a total of 4424 kbps available, and my ISP (Verizon) allocates 864 for upstream and leaves the remainder for upstream, giving me ADSL service. They could just as easily have allocated 2112 each way for SDSL or, if I had some special application where I needed it, 864 down and 3360 up for ADSL. --Blrfl 07:50, 16 May 2005 (UTC)

Actually, there IS a good technical reason for ADSL: at the customer end, the UPlink signal being transmitted by the modem is strong and the DOWNling signal being transmitted by the DSLAM is weak, whereas it's the other way around at the CO end. Crosstalk is much more likely to be an issue at the CO end, where local loops from a number of customers are physically close together. So the S/N is often better for DOWNLlink than for UPlink. It was good fortune that the average customer wants more speed downloading, hence ADSL made lemonade from this particular lemon.

External link

First external link is dead.

Internet Speed Calculator

There should be a calculator where you input a filesize and it outputs the time required to download/view that file on different internet speeds.

There are plenty online. -Omegatron 02:50, August 22, 2005 (UTC)

DSL Repeater

Can someone explain why there are no DSL repeaters to extend the range of DSL usage? Seems like it would be simple to have a line-powered repeater to regenerate the signal and extend the range.

See: http://en.wikipedia.org/wiki/Broadband_Internet_access#DSL_repeater Xaosflux 05:45, 11 November 2005 (UTC)

PPPoE, PPPoA

The articles states:

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.

If I understand correctly, this is the ATM layer referred to in PPPoA, in which case it should read "ATM or Ethernet layer," seeing as PPPoE is more common in the US. Can someone verify this?

Scorpiuss 18:55, 14 December 2005 (UTC)

I believe that ATM is the transport over DSL whether PPPoA or PPPoE is used. These protocols are ways to establish point to point serial connections and refer to the interface that PPP talks to. In PPPoA, the PPP part happens in the modem which is ATM and is before encapsulation of Ethernet has occurred, hence the name I suppose. Snafflekid 22:11, 14 December 2005 (UTC)

Inventors of DSL

DSL was originally invented in 1988 by two Bellcore research managers: Charlie Judice and Ray Laane and by one marketing manager, Manny Kline, from NYNEX which is now part of Verizon. HDSL had already been developed as a technology replacement for T-1 carrier which was used by the telcos for provisioning DS1 service --- a full duplex service. It was our observation that the primary applications for a residential service (video-on-demand and internet access) did not require a high bit rate upstream signal. Furthermore, we understood that in order for a residential DSL service to make sence it had to work on one pair of wires. Within a day with the help of a Bellcore engineer, Joe Lechleider, we demonstrated that an asymetric service called ADSL was possible.

question from a dialup user

from the way this is worded, it seems that anyone with a phone line can use DSL.. i've been on 56k dialup since 1998, and i know virtually nothing about any form of high-speed internet. ? - Srrrrrrr 08:14, 5 January 2006 (UTC)

There's more to it than just having a phone line. Your telephone company has to (a) offer the service in the first place and (b) install special equipment in the central office nearest you that puts the service on your line. I'll take a look at the article to see if it needs tweaking to clarify that. --Blrfl Jan 13, 2006