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The Internet

Homebrew S/ADSL 161

Posted by emmett from the rolling-my-own dept.
schvin writes: "ISP Planet has a brief article about rolling your own DSL connection. One person in Washington state has extensive information on how he got his home-brewed SDSL fully functional." This is great, and I wish I knew about it before I had all this hooked up here. Save money! Do it yourself! It's the GNU way!
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Homebrew S/ADSL More

Homebrew S/ADSL

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  • Re:Dry pair? (Score:1)

    by Anonymous Coward
    As he mentioned, a *Dry Pair* is sometimes also called an *Alarm Circuit*. Do some social engineering and call your local home security company (one that offers 24/7 monitoring) and see if you can find out how much they have to pay for the lines. What they do with them is connect to the alarm system in your house and them to their monitoring center at their office.

  • Re:Yes, actually-- but complex. (Score:1)

    by Anonymous Coward
    It's a bit more complicated, though. The systems require a head-end translator that shifts the frequency up/down by 192.25 MHz (mid-split design). For example, if your modem transmits on 52 Mhz, it will receive on 244.25 MHz. Your neighbor will Rx and TX similarly. He will receive the signal you transmitted on 52 on his rx frequency of 244.25. The signal makes the trip all of the way to the head-end of the cable plant, with amplifiers along the way, each way. The specs were pretty tight, as well. Across the 18 Mhz bands, the amplification across the band had to be flat within a few dB for it to be stable. We used ChipComm brand modems for this about 10 years ago.

  • CenturyTel doesn't allow Dry Pairs here (Score:1)

    by Anonymous Coward
    Well, the method with Dry Pairs is very nice. However, CenturyTel yanked that as an option - right after we beat them on a big bid providing DSL (this was a couple of years ago).

    Maybe we'll have to give them a call.
  • he was joking you fool. get it. HA HA, i thought it was funny anyway as im sure most people did, it was moderated up to 3 "funny"
  • heh, `unlimited' dialup access is available here, too (though I'm not sure of the conditions). At the time I signed up, I couldn't affort the extra $15,. now, I'm too lazy to change over (espacially as I have my own domain being hosted by my isp). Also, I only have one phone :(
  • Ouch. I'm paying $30NZ for 250 hours per month. Whatever happenned to everyting in NZ being more expensive than AU? :)
  • I don't belive I have ever had my PacBell installed Alcatel hang on me.
    Also why wait a minute? 5 seconds should be long enough?

  • Sorry, just being a shit:

    Technically modems don't modulate either; nowadays they encode and decode. The DSP just selects the correct output sequence to hit the right phase and amplitude of the sinewave from a trellis pattern stored in ROM. Decode just watches the line and converts the precieved amplitude and phase back into a bit sequence.

    I don't think I've seen a real modem since the old 2400 baud jobs.

  • That a new expansion of B8ZS by me, I've seen Bipolar, with 8-Zero Substitution from the telcos

    THAT'S IT... I knew it didn't sound right but I couldn't make any other words work. And I was pretty sure that AMI and B8ZS were competing formats but I couldn't work that out with my expansion of B8ZS. :-) Thank you for clearing it up!

    You can get a T3, and it carries a DS3.

    That's news to me... I thought DS3s were always carried over something optical because there'd be too much trouble doing 45mbit over copper for any kind of distance and with any kind of reliability.

  • Let me know when I can order a "dry fibre pair" from my local telco, and I'll join you. ;)
  • This is exactly what my cable modem service was like three years ago. They would secretly reboot stuff all the time without telling anybody and it was impossible to talk to anybody with a clue.

    It use to be some dumbass cable installer who didn't know anything except what signal levels he was supposed to look for. Nowadays, everybody I talk to at the cable company is using the service so I don't hear dumb answers like "Reboot your PC, it will fix the flashing light on your cable modem!"

    Hang in there while they will get their act together or they will be replaced. It's that simple.
  • Good luck trying to get those anymore, most of the major telcos have refused to provision them.

    Even then, they sure as hell won't condition them if it competes with their own DSL service (even if you are in a non-serviced area)

    Oh, and since he had no idea why they were designed to be connected to a switch... sounds like they are 'dumb' bridges... everything is forwarded. Thus the switch is needed to cut down the amount of traffic sent. Better would be to route it (just use an ethernet port on your router and a crossover.) BEST would be a v.35 interface...

    --Dan

  • We must have gotten a dud set. I'm running over 24 or 22 gauge copper a short enough distance to be heard if I yell really loud. At times we get 2k (yes, 2000) bytes/second. I believe they were XL1502 or similar.
    They are getting swapped out soon...
  • You get a zero because everybody who posts anonymously gets a zero, and you need to have a user account, so that you're eligible to have your posts start at +1, and so that you'll be in the moderator pool eventually (or in 2 days at the rate Slashdot is growing).
    The guy two posts up from you got moderated down from a zero to a -1 because some of the moderators here either need their medication adjusted or they're jerks or idiots or some combination thereof. That's why we need people like you in the eligible to moderate category.
  • As someone else explained, a dry pair, is just a set of wires connecting the two points. I don't believe that the phone co. even runs power to them. So the distance, realistically is irrelevant. Once the wire is in the ground, if they get $0.05 a month from you for it, it's essentially found money. They have virtually no costs, once it's buried. And they do bury a ton of it, so that they have lots of room to grow in the future.
  • In a word, bottlenecks.

    With a cable modem (bizarre term in and of itself. ITS NOT A MODEM) you share the total theoretical bandwidth with all your neighbors. This is great, if nobody in the area owns a computer, you have the whole pipe to yourself. But if all your neighbors are sucking down porn of the newsgroups, and hoovering warez from FTP's, your speed will plummet.

    With a DSL line, the connection between you, and your service provider, is a constant, flat rate. No matter what your neighbors do, you never slow down. Theoretically. There is a potential bottleneck tho, your service provider, has to have a big enough pipe from their office, to the internet to support all the users. But since most of the time it's a phone company, they can certainly afford the pipe(s) out to the net.
  • This isn't what most people think of, when they hear DSL line. This is a point to point network connection, nothing more. This is not a way to get on the net cheap, it's just a way to establish a MAN (metropolitan area network). You still need an ISP somewhere, to actually provide a connection to the internet.

    It's a helluva deal, for a remote office connectivity point, but it's not an internet connection.
  • First its a very inexpensive way to setup a WAN. 56k frames from the big telcos cost hundreds a month and if you can get a line for 20 bucks a month that is nice. You obviously would lose a lot of features like data would have to go to one central location then be routed to the other locations (if you have a location in harford and LA and Chicago) where with a frame it would be able to route its self. You would also lose the ability to do voice and what not... but it makes you wonder if you can hook your expensive systems right up to this line and if they would work.

    But on another note I am not sure finding another location would be that difficult if the only thing that matters is the distance between the location and the phone company on either side is what matters. This guy that wrote the article has an ISP and I bet he would be willing (for like 30 bucks a month bringing the total cost to 50 a month) to let her setup to him. But I could be incorrect maybe I am missing something and maybe this person is using the same telco building for both connections which would mean maybe everything would have to be done locally (which would suck)... but I sent him a few questions about this and I hope he will respond.


    --MD--
  • Somebody help me get up support for DSL here in Ranburne, AL =)
  • Does anyone know if this kind of circuit can be set up between two sites that have different telcos? I have a site in a rural location (serviced by CenturyTel) and would like more bandwidth between it and my site (it's on a dedicated 33.6k dialup, ugh) - but my site is serviced by USWest.

    Anyone know if this is possible?

    --

  • Yes, but before the days of frame-relay T1s, a T1 was run over plain point-to-point copper circuit, correct?

    As I understand it an "analog phone line" as a copper loop terminated at the CO with analog signaling equipment to provide a dial tone, and the only thing making it "analog" is the analog eq at the CO.

    And since an alarm monitoring circuit/dry pair/whatever is just a p-t-p circuit _not_ terminated at the CO's analog eq, I see no problem with some CSU/DSU eq on either end.

    Of course, I certainly have no first-hand experience. Forgive my ignorance if I'm incorrect.

    --

  • Only problem being that DSL isn't available at the other location, as it's quite rural.

    But, thanks for the feedback.

    --

  • T1... (Score:1)

    by Phexro ( 9814 )
    FWIW, I believe you can also slap a CSU/DSU and router on each end and have a "T1".

    At least, that is what I have heard in the past.

    Of course, DSL routers are much less expensive than a Cisco 1600 and CSU/DSU.

    --

  • Why is it illegal for good reason?

    What is legal/illegal about connecting up stuff to a copper wire pair?

    I can understand not running a charge of a million volts down the wire and using it to send out extra long wave radio tranmissions of stuff, but as long as your equipment at both ends falls into spec what does it matter what signal you send over it?
  • I don't know if I'm just dense or I was just OVERLY CONFUSED BY HIS ODD USE OF LARGE TEXT but I'm not completely clear on what this guy did. or why he did it. Here's my best guess, can somebody onfirm?

    He installed a point to point connection between two DSL modems. They were connected by two sets of lines running from the CO to the two sites with the modems that only costs $20/mo so his total cost is the initial equipment and $40/mo. Doesn't sound like he's saving a boatload of dough to me but if he's getting the service where it's otherwise unavailable then that's pretty cool.

  • These type of lines used to be cheap and plentiful when they were primarily used to connect burglar alarm monitoring companies to their customers.

    When people discovered that they were great for cheap high-speed data links, Ma Bell pulled the tariff and stopped renting dry pairs. She didn't want competition for her grossly overpriced ISDN and T1 circuits.

    Bell Titanic is going to be the first against the wall when the revolution comes.

  • Yes, actually (Score:2)

    by Anonymous Coward
    There is an old ethernet standard called 10broad36. This means 10Mbits, broadband, 3600 meters (about 2.25 miles) maximum segment length. If you find two of these transcievers you can link up with someone on the same physical coax segment. Of course the line amplifiers have to be bidirectional for this to work. I have done it and it works quite well.

  • Most telcos don't offer dry copper (Score:2)

    by Anonymous Coward

    I used to do this in Hudson, Ohio, but the
    local satanic cult, er, telco (Alltel) got the
    state utilities commission to stop requiring that
    they offer it.

    They would much rather sell you DSL or T-1's
    since they bring in more money for the same
    amount of work.

  • Nothing new here... (Score:2)

    by Anonymous Coward
    This has been done, literally, for years. Using dry pairs - normal 1FBs or 1FRs with the load coils removed - as a high-speed, point-to-point network connection has been done for years in the more rural parts of the USA. And yes, some Baby Bells have taken dry pairs out of the tariff for this reason.
  • DSLAM......is that acronym a creation of yours, or the phone company?
    According to the dslreports.com knowledge base [dslreports.com], "DSLAM" means "digital subscriber line access multiplexer". It's the device placed in the CO that accepts all the DSL lines.

    --
  • Just out of curiosity, what was the problem with the router? I happen to have a Flowpoint 2200, and just recently I had all kinds of downtime. My ISP checked everything out repeatedly, the loop was good, the signal was strong, etc.. etc... Then they replaced the 2200 with another identical one, and the problem got slightly better. I'm just wondering if the Flowpoint 2200 may just not be a very good box.
    -Chuck
  • It's very unlikely. While DSL runs over the telephone network, and telcos are at least somewhat flexible about the service they provide, cable modem service is provided over the same wiring that your cable TV service is on. The cable company isn't exactly likely to let you transmit whatever you like over their cabling.

    What's more, in places that don't already have cable modem service, the cable network is often unidirectional - you can't send data back to the cable company, let alone to any other customers. This is even the case in a few places with cable modems, where you end up uploading over a standard modem and downloading over cable.

    Of course, you could always run your own cable, but if you do that, you're much better off using standard copper or fiber-optics with equipment that's not meant for data over cable TV.

    Disclaimer: I am not a telephone/cable technician. :)
  • ...for a solution that works on a 45,000 foot loop. :-(

    Yeah, there's gDSL [godigital.com], but I have to somehow convince my local phone company (Cascade Utilities, which has about 20,000 customers statewide as far as I can tell) to buy that equipment.

    Man...living in BFE has its advantages and disadvantages...

    New XFMail home page [slappy.org]

    /bin/tcsh: Try it; you'll like it.

  • Actually most T1s these days are just HDSL to the telco, then (usually) on a frame cloud. Parigain/Adtran units are on the wall and provide a DSX-1 port to your DSU/CSU. The line quality can actually be quite a bit shittier for an HDSL connection than a HDSL2 connection, since you're distributing the "load" over two pair instead of one. Go read up on it at Adtran's site. They have great documentation.

    How do I know? I'm the technical admin for a small (500 customer) ISP.

  • He is getting the line for that much, not the internet connectivity. At one end of the line is (his) ISP which has to pay for it's T1 and upstream ISP service.

    So if all you want to do is to get a point to point connection, say to the office LAN, it might be a savings, but if you are after internet access, you have to pay for that at some point.

    --
  • It is unlikely that the physical connections between the users and the telcos were down, however it is quite easy for other problems to cause large scale outages.

    1) The DSLAM craps out in the CO
    2) The frame-relay or ATM or whatever upstream link to the ISP is misconfigured or has a hardware failure or a line cut.
    3) The ISP is the one having the problem (not in your case apparently)

    In the case of Covad, since they colocate equipment in the CO's of local telco monopolies, I imagine it is harder to diagnose and fix hardware problems. Not that the telcos are necessarily better. I had an 8 hour outage caused by GTE losing a frame relay switch and having to readd routes by hand because the backup was misconfigured.

    Also know that DSL customers are last on the list of services to be reconnected if there is a major problem. Voice users, frame relay and other leased line users with Quality of Service contraces are ahead in line. T1 is probably a good choice for you if you need reliability. Better yet, get a backup link over a geographically and network topologically distinct link. The network topology is impossible to determine by guessing since many providers cross link and rent lines from eachother, so make sure you ask, you may not be as redundant as you think.

    My SO works at a major ISP and they lost WAN access between two offices (fiber link provided by Level 3), telephone service to another office and lost connections to thousands of UUNet POPs all because of a fire in a single MCI WorldCom facility. It took them over an hour to realize that there was a single cause. It turned out that Level 3 rented the fiber from WorldComm, UUNet is of course a subsidary of WorldCom and I can't remember exactly how the voice lines were involved.
    --
  • I realize you are asking a hypothetical question, but wireless LAN technology, like Lucent's WaveLAN will go quite a distance (about a mile line of sight IIRC) with appropriate antennas on both ends. The link can be encrypted to avoid snooping.
    --
  • Short answer... you're out of luck unless your next door neighbor has a T1 and you can string cable over the fence.

    The biggest problem is that you need an ISP or something else with fast enough internet access at the other end. DSL is just a point to point link and does not imply internet connectivity. So if you find an extremly friendly ISP or you are in good with the LAN guys at work and they are on the same CO as you and the telco is willing to sell the dry pair then you might be able to make it work. However you will still run into the length problem, only compounded now because the line now goes to the CO and then from the CO to the terminating end.
    --
  • $700, $1200 - whatever. Costs about the same as a CSU/DSU. QoS is far worse, sure, but he's still getting a huge deal, one that most phone companies simply wouldn't allow. Call up your local telco and ask for a dry pair, and they're either gone (If you live in Ca., like me) or cost a couple hundred a month. This guy has some cool God-company that knowingly lets him do this (simply unheard of these days) and doesn't jack his rates up, which they could legally do. Hence my contention that he's getting a kickass bargain that's practically a T1. I think the only reason this is happening is because he lives in a rural area where most of the copper isn't being used. All that extra RF that a DSL signal would spit out would certainly not go unnoticed in a populated area.

    --

  • Re:T1... (Score:2)

    by drix ( 4602 )
    Alright time to clue me in - AFAICT this is neither digital nor analog. It's a big wire running from point A to point B. No matter how you're transmitting the signal, digitally, analog, whatever, I don't get the analog/digital circuit distinction.

    --
  • What an asinine comment. It's perfectly legal and a lot of people have done it.

    --
  • I never did understand the whole dry pair deal, although I've heard of people doing this before. I seems like running 5 miles of copper cable would cost a lot more than twenty bucks a month.. what am I missing here?

    --

  • Monopolies suck. Here I have a 512/128 ADSL at home. Fine, you'd think. WAIT! How long will it take you to roll on the floor laughing when I tell you that the minimum ping I get i s... taddam ... 130ms!!! And averages more around 300ms. That's right! Worse than a 28.8 modem! But wait, it gets funnier! Last nite at ~1AM, I was at 600ms with 20kbps throughput. Impressive isn't it? And no, it's not the ISP, since connecting via my good old 28.8 yielded much, much better numbers.

    No, it's the infrastructure laid out by France Telecom that sucks big time. Behind the DSLAMs lie a totally overloaded ATM network that links to the ISPs. FT allows them 3.6kbps per subscriber!!! Of course, not everybody uses them at the same time. STILL! It's a completely fucked up estimate they made

    People are complaining: there is an estimate 4000 subscribers to this "service". Over 1000 have registered on this ADSL users [adsl-france.org] website.

    WRT SDSL: there is one company in Paris (Proxad [proxad.net]) that does the same as our guy: they rent copper cables, and put SDSL modem at each ends. Very competitive compared with LL here, still very expensive though. ~$600 for a 256k.

  • Here in Charlottesville, VA, our biggest ISP [cstone.net] was using this method. It actually may be illegal to do that here, as Virginia is one of the states that grants "de jure" recognition of monopoly status to, for example, Virginia Power and various ILECs. They (the utilities) have to go through a bunch of red tape to change prices and such, and they have to do it in accordance with the "tariffs" for a service, which detail what product you're providing, what it's for and what prices you can charge.

    As the above poster pointed out, DSL emits imperial buttloads (bigger than your puny metric buttload!) of RF. Our ILEC is Sprint; after CStone had about a half-dozen of these "DSL" installs, Sprint figured it out and told them it was a service outside the tariff specs, it was causing noise on other lines in the same sheath, and they wouldn't be doing any more dry-pair installs for CStone as a result. There was a bunch of other maeuvering but I can't go into detail as it was specified that it was all "off the record" during the conversations I had.

    My personal opinion is yes, it causes quality problems, but Sprint came down hard on it not because of the quality (which they manifestly don't care about, judging by my experiences with them) but because they realized they were missing out (they had several months yet until their own DSL service was launched).

    CStone was recently bought by a regional CLEC/ISP/cableco [cfw.com], so theoretically they might get to slap their brand on CFW-provided DSL at some point. CFW's been doing DSL here since March of last year and (apart from various incompetence with actually getting an install tech out!) I love it to death. 768K for $70.00/mo. (384K for $50) -- my friends in Northern Virginia hate me :-)

    Summary: Don't abuse it or you'll lose it.

  • Actually, as I understand it, a dry pair is just a plain copper circuit from one location to another, without the "dial tone" on it. Since the telco already has copper to both premesis, it is just a matter of hooking them up to each other at the CO.

    A T1 _used_ to be basically the same thing, but with a guaranteed line quality. The telcos are just bastards and overcharged/overcharge for it.

    Nowadays, most T1-type circuits are run over a telco frame relay cloud instead of a straight circuit.

    I don't know if the "alarm circuit" connections are also run over a frame cloud, or if it's the older style circuit.

    --

  • Admittedly, this isn't directly related to the topic at hand, but it's an interesting fact: Yesterday, my company's DSL connection was out for approximately 12 hours (at least 7am to 6pm, probably a bit longer, 6 was when I last tried it). Apparently a large swathe of Los Angeles went down with us, so it was a severe problem that affected many people.

    Our ISP (Concentric) said it was a Covad problem and they had no idea when it would be fixed. Covad said they had no idea when it would be fixed. Everyone I spoke to was reasonable, courteous and clueless.

    This article makes me think DSL connections are pretty simple. What could cause such a long outage?

    I had already convinced my company to upgrade to a conventional T1 due to reliability issues; now everyone in the company understands why I did it :-).

    D

    ----
  • I am a bit fed up with my bouncy line so I've done some research...

    http://www.3com.com/solutions/dsl/dsl_technical. html - a good backgrounder
    http://china.si.umich.edu/telecom/telecom-info.h tml - good set of links on telcos(if you got hours to spend :)
    http://www.netopia.com/equipment/dslcenter/order /index.html - Netopia DSL equipment ($500 for 1.5mbps integrated router typically)
    http://www.dslsource.com/glossary.html - glossary of terms
    http://www.pcwebopedia.com/TERM/x/xDSL.html - definition/links

    This should get you started ;-)

    If you are able to get through the sales barrier, you should know what you are talking about and be armed with facts when they try to tell you it won't work.
    --
    Leonid S. Knyshov
    Network Administrator
  • This isn't really new.. though perhaps there are some misconceptions about what adsl really is (or xdsl..)

    The whole big huha about adsl originally was that it would work over our existing copper infrastructure. This means, anyone with a dry pair between two places can use DSL. Period. So long as the distance requirements are met. It is not something that is specific to a phone company, or something requiring 'special' switches.
    Many ISP's (at least, here in Canada) actually lease loops off the telco and run their own DSL services.
    Now.. certainly, the telco is in the best position to know their own network (you would think..).. and in the best postiion to centrally roll thinsg out (racks of DSL devices in their switching center.. half the distance others would need to go..e tc..) but anyone can do this.
    So. Go to it! Dry pair is cheap...
    The hard part, usually, is finding the ISP who is willing to let you drop your equipment in there. They'll probably want to charge you an arm and a leg.
  • Not necessarily the same as a 56k circuit, though many parts of it might be.
    Charges for local loop of normal plain jane dry copper are generally super cheap. It's just not a common sale.
  • what you say about the fresnel zone is true, however.. I must say. Wireless IS very good, even in unlicensed ISM bands. Certainly, it's not for everyone, but if you can engineer the link, they do work well.

    It's too bad we don't see more 915Mhz ISM products out there... 915 is much less succeptible to reflection, and you can clip trees without too much difficulty.

    Of course, bandwidth tends to be a bit lower, but I've had 1.5Mbps links going over 900Mhz ISM..
    even across the top of a small forest (read: there were a few trees in the way, but not many)
    approx.
  • MODEM: acronym for modulator/demodulator.

    Does a cable 'modem' modulate? Yes. It modulates a baseband signal like ethernet up into RF for cable transmission.
    Does it demodulate? yes. It demodulates RF back into baseband for ethernet transmission.

    So it most definately is a modem!
  • Which is better usually has a great deal more to do with the ability of the respective companies to manage their networks and their commitment to quality service.

    yes, with DSl, most bottlenecks happen at the telco, where it is easier to deal with bottlenecks. however.. the ways telco's build their networks (many places would be surprised how un-centralized telco DSL services are) such that there are many nocs all around town.. and network congestion is as much a problem as anywhere else.

    Also, cable technically has more bandwidth.

    Take your pick.
  • Oh.. yeah.
    wavelan cards (and proxim, and several others) can go about 10 miles with NO signal amps, only using proper antennaes.
    I've done 14km links using proxim rangelan II cards (100mW, I believe) using some simple yagis.

    One has to be careful with inline amplifiers, as you may exceed allowable power levels.
  • Umm... $40/mo for both ends? Very good deal.
    Except in places where telco's have graciously deployed DSL services, the ONLY high speed digital services you can get cost a LOT of money.
  • Nothing is different. It's the same line.

    What makes the line between you and your friends house unsuitable is there IS no line between you and your friends house. Not unless the telco is nice and punches it down in the right places.

    With DSL at your house, the telco has a DSL modem on the other end of the line, and you have one on your end. This is someone doing the same thing, but leaving the telco out of it.

    To put it differently, DSL is just a service that is provided over standard telco copper (just like dialtone service for your voice calls).
    Nothing prevents you from ordering 'dead' lines and doing what you want with them.
  • Not without a 2 pair, balanced line you can't.
    And the line quality required is higher for T1.
    And if I'm not mistaken, there are other line drivers needed as well.

  • 1) find an ISP to provide you with IP.
    2) Lease a dry pair off the telco, from your ISP to your end location. Make sure it's within the allowable distance limits for adsl
    3) Get the DSL gear, and away you go.
  • no updating required. DSL works over plain bare copper.
  • What is the distance between the two locations?
  • Just to shed a light on the situation here: Some years ago, it was still possible to get plain copper starting at a rather cheap 60 DM/month (1 DM ~ $0.50). Of course, this was voice grade, but you could still run modems on it. I had such a line in 93, but the local user group whose router I connected to suddenly wanted root permissions on my machines "to be able to control misuse of bandwidth" (or so they phrased it - I wonder if they knew what a router could do, they could have simply dropped packets if they considered the traffic misuse). Of course, I only got told that after shelling out like ~2.500 DM for installation and equipment and six months of 120 DM/month. The line didn't even work the first three months because Linux didn't support PPP at the time and they claimed to have forgotten the password for the access router, so they couldn't switch to SLIP for my line - of course, it would just have taken somebody to actually drive there and sit down at the console.

    After this experience I kept checking out alternative solutions, after all, modems didn't really cut it even back than. But by pure coincidence, when the restrictions on equipment connected to these copper lines were dropped (they had to be officially approved for use on the german telecom network first), suddenly bandwidth limiters popped up. Suddenly the telco remembered that they were only obliged to sell 3,1 kHz voice grade service over that copper lines, so they put in filters. You could still get lines without filters if you claimed you wanted to connect two old telex boxes, but you had to show them, and of course you still weren't allowed to run DSL on that line. If there were problems, you were not only alone with them, but the telco could actually sue you if your DSL-signals interfered with other services.

    And suddenly the Telekom decides that you _can_ do ADSL, but only in selected areas and if you rent their equipment. Private accounts only have DynIP, run at 768/128, costing 100 DM/Month (including ISDN service) plus 0.03 DM/Minute. Commercial accounts start at ~300 DM/Month (for 768/128, available up to 6144/512) and are basically a leased line configuration with static IP and metered by traffic (~100 DM/GB, depending on total traffic usage).

    Still, for many users this is the best offer around. I am using it right now. RTT is around 30ms, which is not really better than ISDN, but comparable, and the throughput is usually ok.

    So, before you start bitching about your phone companies, have a look over here and begin feeling better... :)
  • I live in Phoenix, Arizona. One would think that I would be able to get xDSL in some manner (from USWest or someone else), but I can't. At least, that is what they tell me.

    You see, I am on the "edge" of Phoenix - actually, smack-dab in the middle between Phoenix and the Cave Creek/Carefree area. North of me are tons of new subdevelopments, south of me (actually, a stone's throw) is the Loop 101 freeway (new freeway extension). I moved out here because the rent was cheap and the area was quiet (I used to live downtown, and gunfire was an occasional noise). A mere month before I moved, my apartment complex could finally "get" xDSL from USWest. I didn't check on services in the area I was moving to, because the deal was too good to ignore. So I moved.

    Now, I can't get xDSL. I have argued and complained with USWest, with no luck - they say they can't do it (too much line noise - what they call "slack" or something). I can get Cox@Home service, so that is an option available to me, and one that I am thinking about. However, I would like to find out if anyone has any advice on some other ideas I have had:

    1. My neighbor has Cox@Home - he lives right next door, and the distance between the two houses is about 200 feet. I am thinking setting up an IMASQed box (maybe with a firewall - this is all new to me, but I am willing to do it and learn, so bear with me if I have anything wrong), that his cable "modem" will run into, and then serve his machine, and then via a long run of CAT-5 TP, send an ethernet connection to me. Then I would pay him half his bill for the connection.

    2. On the other side of my house is a couple of large businesses (the area can be zoned residential and commercial, so this is common here), one of which has a microwave tower of some sort, so I know they have big comms of some capability. I thinking doing the same with them, and paying them for service.

    3. On a walk yesterday, I noticed a box not more than 1000 feet from my house labled "USWest HDSL Doubler". It was a pretty large box (about the size of a filing cabinet). After finding out what an HDSL doubler was (doubles the line distance HDSL can work at), I wondered why I couldn't at least get HDSL to my house. So, maybe I can argue with USWest about this and get connected (fat chance, but might be fun to try).

    So, which option do you think might be best to pursue? Option one sounds the simplest, but it also sounds like the "cheapskate" method (I am not adverse to paying for the bandwidth, but given my last experience with getting my cable hooked up, I am reluctant to call COX again). The second option is iffy at best, and the third a long shot.

    Does anybody have a suggestion that is relatively low cost to implement that I haven't thought of? Or at least comments on what I have thought of? Thanks in advance!
  • but being stuck here in Western Australia, DSL is still something our telco's are investigating.

    <points madly at the USA> LOOK! IT WORKS! I'm expecting it to take another couple of years before we can get this technology you lucky few take for granted. And even then I'll bet we'll all be paying a fortune for it.

    I don't know if I'd be brave enough to try that homebrew thing though.

  • Although, for lack of detail...I am assuming he ordered from his telco, what my telco refers to as a 56k circuit. *he just called them a pair of copper lines*.

    Be forwarned these prices vary greatly...pricing is dependant upon distance between the points, whether or not they are in the same exchange, term of service, and whatever happens to be the basic rate. Just guessing...around here that would cost a few hundred a month with a long term contract *install fee's are usually nominal*.

    I was surprised at how inexpensive the charges from his local telco were. (Unfortunately for
    me living in southern ohio has its disadvantages).

    After that...you have a clean circuit between the two points. I haven't *yet* attempted to use a set of dsl modems though.

    Anyone else tried this and had promising results *preferably with a little more technical details thrown into the mix*.


  • Not as funny as you think. I know I read about people doing this a couple years ago with one of the big baby Bell companies (I think it was in comp.dcom.telecom.) After they found out what was going on they nipped it in the bud.

    The problem is that you can't just get a dry pair and hook anything you like up to it. That's actually illegal for a good reason. So the telco (damn I wish I could find that article) has a right to tell you that you can't hook up DSL to a dry pair. This sucks because they use this for an excuse to prevent people doing exactly as this guy is.

    Perhaps CenturyTel is as cool as this guy says, but trust me, the big guys ARE NOT.

    numb
  • Why is it illegal for good reason? What is legal/illegal about connecting up stuff to a copper wire pair?

    Nothing as long as you own the wire and aren't violating FCC regs. If there were no laws regarding what is hooked into the public network people would hook up whatever they wanted without regard to who else in the bundle they are interfering with. It's not just extra long wave radio transmissions you have to worry about when wires are bundled so tightly together.

    I can understand not running a charge of a million volts down the wire and using it to send out extra long wave radio tranmissions of stuff, but as long as your equipment at both ends falls into spec what does it matter what signal you send over it?

    You can understand, but don't count on every idiot with a telephone line to understand. If the wire can handle it without screwing everyone else up, then I personally have no problem with hooking the device up.

    So: 1) Having laws restricting what you may hook up to the public telephone network is a good thing. 2) Telco's using that law soley to prevent people from obtaining cheap high speed Net access is a bad thing. 3) Apparently some telcos care more about making money than whether something is a good thing or bad thing.

    numb
  • Bob Metcalfe [infoworld.com], who seems to be a hated figure amongst slashdotters, mentioned using regular copper as DSL-equivilant almost three years ago in this article [infoworld.com] dated July. 7, 1997.

    Here's an excerpt:

    The good news is that some of you can already buy inexpensive coppertone from telopolies. My ISP and I got some coppertone just last week. Now, don't ask anyone at your telephone company for coppertone or HDSL; this will get you nowhere. Instead, order a "burglar-alarm circuit," put some HDSL electronics at each end, and bingo, you can have 1.5Mbps for a fraction of what telopolies charge for T1 lines.

    So give the guy some credit!
  • That sucks :(.

  • I can't get cable modem and ADSL services in my home area (near Los Angeles). I was told my house was too far from the CO (GTE). However, I can get IDSL (144kb/sec both ways) connection but it is too expensive for my budget. Would this homebrew work for me if I were to build one or have someone build it for me? Or do I still face complications (i.e. distance)?

    How much would this cost and how complex? I hate being with my 26400 modem connections (get about 2.8KB/sec) on a 56K modem. Telecommuting is impossible! :(

    Thank you in advance for replies.


  • I agree. In New Brunswick Canada, where I live, there is $70 instalation and then $40 / moonth thereafter (thats CDN mind you, more like 45/25 american). And my speeds are a bit higher than he mentioned. On a side note, I don't think this guy can be much of a geek... when I read "! THAT is why DSL can be so over sold! Who can use that much bandwidth for more than a few seconds at a time normally!", i was like, this guy has obviously never downloaded large ISO's on a constant basis. Waiting an Hour for an ISO download drive sme nuts!

  • Knowing how the rest of the world is, you guys will be paying by the bit. Must suck to be you...
  • No, he rented/leased a dry (read, no dial tone) copper cable for $20/mo.

    He bought a pair of dsl switches for $700.

    He is a local isp on the smallish side, previously only offering dial up service.

    He connected his home and a local hostital that was already one of his customers.

    Lets see, what did I miss?

  • Well, this is not your typical "has been done before SlashDot troll", but yes, Egypt has been doing this for a long time.

    I am talking here about Alexandria, Egypt (4.5 Million) and Cairo as well (16 Million), which are not rural at all, and the forces at play are not the same as those mentioned in the article.

    A little bit of background: Egypt has undergone massive telecom infrastructure upgrades in the mid 1980s and early 1990s. The old wiring was almost totally replaced with new wiring, and the switches were replaced from mechanical to electronic.

    This left the old wiring in place, doing nothing. That is until the internet came in the mid 1990s.

    Let me say that Cable TV does not exist in the Middle East (maybe only Qatar), and therefore it is not an option for high speed connections. Also, the phone company in Egypt is a government monopoly (but this may change soon).

    Internet Cafes are very popular in Egypt, since not everyone has a computer, and per-minute charges get to be expensive (read more about it in the Cost of the Net in the Middle East comparison page [2bits.com]).

    An Internet Cafe approaches the ISP for a leased line connection, and they ask the telco to provide the . The ISP provides the rest (modems, ...etc). ISPs are concerned about bandwidth and normally limit this to 33.6Kbps, unless you pay heavily for more.

    Companies having branch offices do the same (but put xDSL technology in place) so they can exchange documents, graphics and more.

    I am glad to say that the internet is improving in Egypt year after year, as compared to other places in the region (read about it in Speed in Jeddah vs. Alexandria page [2bits.com]).

  • by the time you folks are ready to embrace this new tech, we'll all be selling you our old units, used ;-)

    mostly cause we'll have gone back to the old reliable FDDI (or CDDI).

    yeah, that's the ticket - token passing over fiber. what a novel concept. it was SO cost effective, too. none of the problems of *dsl and no funky DSLAMs to have to deal with.

    --

  • here in the bay area, pachell is installing alcatel 1000 modems. aka, 'crash-catel' 1000.

    this unit, along with its mating DSLAM in the co, is the worst POS I've run into in my 15 yrs in the comms industry. its SO highly unreliable - I've had to keep a line monitor on it (really just a software process that pings my default router in the CO and power cycles the modem when the router is unreachable for a preset threshold).

    using some cute X10 boxes (firecracker and such), you can send an rs232 command to power down the crash-catel, wait 1 minute, power it up, wait 30 seconds (its a bridge, it must learn...), log an event to my local graph/file then resume polling again.

    this works! but it was a hassle having to do this to keep the damned boxes in link-sync. sigh...

    if anyone needs the code, I'll email it to them. its very simple stuff - and its saved my butt when I needed to telnet to my home box from work (since there's always 'someone' at home to cycle the line when it hangs. and it DOES hang quite a few times per day!)

    --

  • Nice description, but I can't resist fixing up a few details :)

    Somewhere in the past B8ZS (Bit 8 Zero Set) came along and, with AMI, cleaned up everything.

    That a new expansion of B8ZS by me, I've seen Bipolar, with 8-Zero Substitution from the telcos, Binary 8-Zero Substitution if you ask Cisco, and Binary 8-Zero Suppression from Bay. Your right about it only being of any benifit when used with AMI (Alternate Mark Inversion)

    There are no such things as T2s and T3s, only DS2s and DS3s.

    Not true at all. DS-whatever is a framing standard, and a TS-whatever is a copper pair carrying an electrical signal using the corresponding DS framing. A T1 carries a DS1. You can get a T3, and it carries a DS3. That being said, I've never heard of a T2 - AFAIK DS2s only exist as signals within switching and test equipment.

  • I'm using this method.. works great (Score:3)

    by Crow- ( 35 ) on Tuesday April 04, 2000 @08:41PM (#1150774)
    I live in a rural town as well, population 4000, and at least 60 miles to a town with more than 2 red lights. and i have SDSL here, its fucking sweet.

    my isp has a DSLAM, southwestern bell charged $175 for the dry pair installation, and im not sure what the monthly rate is, its included in the isp cost. I pay $75/month for 400kbps+5ips frame relay, not bad at all since i never thought I would see higher than 28.8 a month ago. The router is a Lucent Pipeline ($600), its pretty nice but is having some problems mentioned by someone else here.. massive packet loss at times and the connection eventually dropping. rebooting seems to have cleared it up though, who knows..

    ascend% show revision
    SCPipe system revision: l.s15 7.10.5

    apparantly the telco was hesitant about allowing the dry pair to be used for this purpose at first but they are required by law to offer the service, no skin off my back.

    fastest transfer rate i've seen is 47K/sec and quake3 pings are normally sub-50.

  • Re:cable v. dsl (Score:3)

    by tzanger ( 1575 ) on Wednesday April 05, 2000 @06:34AM (#1150775) Homepage
    With a DSL line, the connection between you, and your service provider, is a constant, flat rate. No matter what your neighbors do, you never slow down. Theoretically. There is a potential bottleneck tho, your service provider, has to have a big enough pipe from their office, to the internet to support all the users. But since most of the time it's a phone company, they can certainly afford the pipe(s) out to the net.

    Unfortunately most (all?) providers overcommit. The level of overcommit is actually able to go up with the more customers they get because the whole thing shares really well if people are just browsing. Overcommits on dialup-class service can easily hit 100:1 on bandwidth and 7:1 on lines. It works just fine as long as you don't have a two-digit percentage of the people you're overcommitting doing some kind of long high-bandwidth transfer.

    I'm not sure what the numbers are like for DSL/Cable but they can't be much better.. That's a wad of bandwidth they're giving each person and DS3s are neither cheap nor enough to service a lot of 1-meg customers doing fulltime downloads.

  • Re:Cheap? (Score:3)

    by drix ( 4602 ) on Tuesday April 04, 2000 @08:45PM (#1150776) Homepage
    This is low - he is getting symmetric 768kbps DSL for about 20 bucks a month, with a 100% CIR. That's bascially a fractional T1 in all but name. It would cost probably $8000-$10000 per year including ISP service in the real world. I'd say he's getting a steal.

    --

  • Re:Interesting... (Score:3)

    by mzito ( 5482 ) on Tuesday April 04, 2000 @10:35PM (#1150777) Homepage
    The circuit he is talking about is not a 56k circuit. The 56k P-t-P you are talking about is a DS0 w/ 8kb reserved for signaling (64kb - 8kb).


    An alarm pair is (IIRC) a lower-bandwidth P-t-P circuit that is routed differently through the Telco network. Wish I remember more specifics about it, but I've never ordered one myself. There's no QoS guarantee for circuit noise, etc. Caveat Emptor.


    Regarding the actual implementation of this, there was a discussion on this topic on both the ISP-EQUIPMENT and Cisco GroupStudy mailing lists. The general consensus was this:

    1) Make sure the distances from the PoP to the CO is less than 12,000 feet for the best chance.
    2) Not all Bells will allow you to get these unloaded copper pairs, and those that do will often not give you the highest quality circuits.


    I've never done it myself, but there seems to be a fair amount of success in the matter in the marketplace.


    Matt


    Matthew J Zito, CCNA

  • Re:Finally a Solution for Rural Areas (Score:3)

    by unicorn ( 8060 ) on Tuesday April 04, 2000 @08:53PM (#1150778)
    Most likely this won't do much for your mom. The problem is, who's gonna be at the other end of the pair? This is not a DSL line to the internet. It's a high speed connection between 2 places. It's basically a cheap way to set up a MAN (Metropolitan Area Network).

  • $20/mo. dry pair? (Score:3)

    by bjsvec ( 19546 ) on Tuesday April 04, 2000 @08:03PM (#1150779)
    $20/mo. for a dry pair from telco is an incredible deal. Especially for the distances stated (20,000 feet). I have seen customers pay up to $500-$1000 per month to Pacific Bell for an unconditioned dry pair of less then a mile. I suppose the shortage of copper facilities in most areas of No. California may have something to do with this...

    Anyhow, sounds like a great solution at a good price, but readers from various areas should beware that they may find the cost of getting a dry pair through their local telco to be significantly more expensive.

    bjsvec

  • Re:Dry pair? (Score:3)

    by mindstrm ( 20013 ) on Tuesday April 04, 2000 @08:40PM (#1150780)
    And T1 runs over balanced synchronous lines.. known usually (I believe) as HDSL, and they consist of two pairs instead of one, and are rigorously tested for quality.

    T1 is still T1. Frame is still Frame. You're describing different layers.
    Though most ISP's that sell you 'T1' access really just sell you T1 access to a frame cloud, then do whatever from there on out.

    Alarm circuits are single pair copper, exactly what is used in your house for your analog phone, but wihtout the dialtone/switching gear hooked to it.

  • this also works with T1 CSU/DSUs (Score:3)

    by troutman ( 26963 ) on Tuesday April 04, 2000 @08:52PM (#1150781) Homepage
    I have used SDSL or HDSL equipment on both private and telco dry pairs in several installations. Usually, it just fires right up -- especially if one of the end points is literally across the street from the CO! I have used both PairGain and Tut Systems equipment. The PairGain stuff is nicer, but it is way more expensive.

    Some may be surprised to know that you can also do this sort of thing with standard T1 CSU/DSU units, wired up in a cross-over fashion. Set the "line build out" setting to the maximum, and as long as the cabling is less than ~3500 feet, it will work. If the line is of marginal quality you will see some framing and CRC errors. But, it is usually nothing much worse than an average point-to-point telco T1. You can get used CSU/DSUs and routers cheaper than xDSL gear at the moment, too. This also has the advantage of letting you combine voice and data on that "circuit", if you are trying to connect two business locations together as cheaply as possible.

    SDSL will give you 2MBit/second on a single pair of dry copper. HDSL gives you 768kbit/second on a single pair of copper, which can be combined for a 4 wire connection at 1.5Mbit/second (common with PairGain stuff).

    Another little secret of the telcos is that these days almost all "T1" type circuits (including frame relay ports and ISDN PRIs) are actually delivered to you on PairGain or Paradyne type HDSL equipment. These are the so called "smart jacks", the white/gray boxes that you plug your CSU/DSU into on your end. The telco doesn't have to put all of that time into engineering a true "repeatered T1" anymore -- they can just grab some pairs and fire up the HDSL and turn up a T1 circuit in a matter of hours instead of days or weeks. They do this all of the time for their overpriced dedicated circuits, but for some reason they have to spend years "trialing" DSL for mass consumer use. uh-huh.

  • Re:dry copper? (Score:3)

    by Garpenlov ( 34711 ) on Tuesday April 04, 2000 @08:28PM (#1150782) Homepage
    What exactly makes the line between me, and say, my friend's house unsuitable for DSL?

    The fact that there isn't a line between you and your friend's house. Simplifying it a bit (a lot?), there's a line from your house to the CO, and a line from your friend's house to the CO. When you dial your friend's number, the CO switch connects your line to his line. When you hang up, the lines are no longer connected.

    Ok, so you can't use them because there's no dedicated (nailed) connection. It's only there when you ask for it. So, what if you ask for it all the time? Well, you don't have copper running straight from building to building, and at some point your analog signal (you talking into your phone) gets encoded into a digital signal. And only 64 or 56k is allocated for that signal. The lines run from the CO to your house COULD support a lot more than 56k -- but back before phone lines were used for anything more than phones, there was no reason to, and every reason not to: aggregating 24 64k channels = 1 T1. What if each channel was, well, 768k?

    One more thing that should be pointed out for this article is... the "roll your own DSL" is somewhat confusing. The guy that did it could do it, because he already had a connection to the internet. The "roll your own dsl" part was the fact that he was then able to connect other people to him, via phone lines / DSL modems. Just don't expect to buy some DSL modems, order a dry circuit, and magically have internet connectivity..

  • dry copper? (Score:3)

    by eries ( 71365 ) <slashdot-ericNO@SPAMsneakemail.com> on Tuesday April 04, 2000 @08:06PM (#1150783) Homepage
    Could someone who knows way more than me explain what the difference between "dry" copper and the existing structure of a line between me and the phone company. What exactly makes the line between me, and say, my friend's house unsuitable for DSL?

    Sorry for the basic question, but I have DSL in my house and still don't quite get it... Is this similar to the various "home network over your existing phone line" offerings?

    Want to work at Transmeta? Hedgefund.net? AT&T?

  • Cheap? (Score:3)

    by _marshall ( 71584 ) on Tuesday April 04, 2000 @08:22PM (#1150784) Homepage
    I think a project on this scale is for people who know what they're doing with routers and networks.

    The article suggests that the cost of one of these 'Do-It-Yerself' DSL lines is low compared to that of the phone companies charges. Where I live, Installation and Modem are free, and its $50.00/month for ISP & Line Service.(GTE) You can't beat a deal like that...(especially since the modems he's talking about are in the $500-$1000 range..) This price provides a constant 768k/128k down/upstream, and makes me perfectly happy.

    --
    Homer: "No beer, No TV make Homer something something";
    Marge: "Go crazy?";
    Homer: "Don't mind if I do!"

  • ok, this is just plain wrong (Score:3)

    by TRoLL. ( 141847 ) on Tuesday April 04, 2000 @08:07PM (#1150785)
    these people are RIPPING OFF THE PHONE COMPANY!!! that is very immoral of them. how would you feel if someone was ripping you off by going around your rules??? the phone company charges like $1000+ a month for this type of stuf!!!! YOU ARE STEALING if you do this!!!!!!!!!

    plus its bad too because there probabley isnt a TOS with this that bans servers!!!! so people would be able to run servers!!!! that is ripping off the corprate sites on the internet!!!! if you want to run a site you gotta pay lots of money to a hosting company!!!! otherwise youre STEALING.

    you ppl need to quit STEALING. IT IS WRONG TO STEAL FROM THE PHONE COMPANY!!!!!!!!!!!!!!!!!!!!!!

  • Two local loops, added distance (Score:4)

    by IGnatius T Foobar ( 4328 ) on Tuesday April 04, 2000 @07:54PM (#1150786) Homepage Journal
    Running short-haul modems (and now, point-to-point DSL equipment) over solid copper circuits has always been an interesting activity. This kind of thing has been getting done for decades in campus type situations, and for organizations that own multiple adjacent buildings.

    The problem with deploying an ISP-style rollout of this technology is that the distance between the telco's central office and the ISP's POP now has to be added to the total length of every circuit. That can make a difference -- as anyone who lives on the outskirts of a town will tell you, with DSL every foot of cable counts!

    I'd like to see this kind of thing tried with IDSL. IDSL uses 2B1Q encoding rather than the G.Lite technology typically used in an ADSL circuit -- it's basically an un-channelized ISDN line that terminates in a DSLAM instead of at the telco switch. The top speed it runs at is only 144kbps, but it can run nearly twice the distance that other DSL technologies can run -- and unlike ADSL and SDSL, the telco can extend IDSL circuits using U-loop repeaters. I'm considering ordering an IDSL circuit for my home.

    Considering that the article we're currently commenting on discusses deployment of broadband in sparsely populated towns, it's likely that the extra distance will come in handy. I wonder if anyone is manufacturing peer IDSL modems?

    --

  • Re:Dry pair? (Score:4)

    by alhaz ( 11039 ) on Tuesday April 04, 2000 @08:16PM (#1150787) Homepage
    The thing is, when the telco wires into an area, they don't just run a few pairs, they run a *Lot* of pairs.

    When you order a dry pair, essentially they just figure out what they have to do to get a connection from point A to point B - this usually goes through any number of cables that converge at various points on regular punchdown blocks.

    The problem is, in many areas, you can't get a dry pair for love or money.

    Well, that's not true, in USWest country, you can get a dry pair for one heck of a lot of money. Classically, yes, they are $20/mo. As soon as USWest figured out people were using them for data, they (legally) priced them as data-capable circuits for several hundred dollars a month, so that they wouldn't hurt their frame relay sales.

    Basically, they now charge about as much for a dry pair as they do for frame relay. So why bother.

    This sounds like he's investing about $1200 per connection in hardware - he might have been able to pull off the same thing using off the shelf wireless gear and directional antennae for about the same money. Wavelan cards with appropriate signal amps and antennae can go 3 or 4 miles easily.

    The real problem with wireless, within a city, tho, is that non-licensed bands require a very clear line of sight.

    The common misconception is that you essentially need a clear area about the size of the transciever element to get from here to there. This is completely, depressingly untrue.

    Pretty much all the unlicensed gear is 2.4ghz - that sounds great, doesn't it? It's not.

    At a 7 mile distance, a 2.4ghz signal needs a corridor fourty feet wide with no obstructions. And just one tree branch in the way can screw with your signal.

    They call this the fresnel zone. 2.4ghz is especially sensitive to obstruction because the leaves of most trees make wonderful quarterwave antennae for the signal, and you get lots of reflection off of solid objects like brick or cement.

    If you're serious about a point to point connection, licensed bands are the way to go. a 23ghz (note the lack of a decimal point) link over the same distance requires more like a 12 foot corridor.

    That's the problem with wireless - the vendors hype it up, but in reality it's actually problematic.

    It's late, and I don't know where I'm going with this. G'nite.

  • Doing HDSL In The UK (Score:4)

    by Joel Rowbottom ( 89350 ) on Tuesday April 04, 2000 @09:52PM (#1150788) Homepage
    You can do this in Britain as well - you need to ask British Telecom for a "Key-line Baseband" line. They'll only do it if both ends are in the same exchange and they don't like selling it, but Mailbox Internet [mailbox.net.uk] sell it as a product in the Fulham area of London.

    Using the Pairgain kit you can drive a single pair up to about 1.1meg, or if you use 4-wire circuits you can get about 2meg. The greater the distance though, the lower the signal, you have to remember that.

    As I recall, Demon [demon.net] used to give it away to their staff as a perk - Mailbox [mailbox.net.uk] seem to be doing that as well now.

    FWIW, we put a link into the local pub, The Southern Cross.

  • It's not necessarily as good as it sounds (Score:4)

    by khiron ( 128206 ) on Tuesday April 04, 2000 @08:32PM (#1150789)
    As an expat Aussie living in NYC I can tell you that the bandwidth is nice when it works, but the local Telco here (Bell Atlantic) are at least 2 orders of magnitude worse than Telecom was as a monopoly at customer service.

    They have Lied out right to me 3 times (that I caught)

    Have inept network techs, but they are level three techs

    To get to a level 3 tech you need to be put on hold for around 3 hours by a level 2 tech.

    Level 2 techs probably have DSL at home, but if you mention Linux, BeOS, Windows 2000, SMP, Home Networks, any setup where there are more cards in your box than a video card and NIC, or any TLA that confuses them you will be put on the not supported treadmill.

    To get to a level 2 tech you need to be put on hold for 4-6 hours (seriously EVERY TIME) by a level 1 tech.

    Level 1 techs may understand english.

    In the past week I have had to manually resynch my modem 5-6 times a day.

    They schedule maintenance where they take down and entire suburbs residential connections, and then bring them back for 1 minute of every 3 for an entire weekend, without ANY publically accessible pre-warning.

    Have no newsgroup

    Have mail and news servers that are thoroughly overloaded.

    And to top it all off, sometimes the bandwidth is slower than a 56k connection, AND I'm paying for the second tier of service.

    It is almost as if they are trying their level best to beat the previous bench mark for the worst customer service ever.

  • I've got dibbs on the first lawsuit. (Score:4)

    by tcd004 ( 134130 ) on Tuesday April 04, 2000 @07:30PM (#1150790) Homepage
    It's only a matter of minutes before the suits jump on this one!

    tcd004
    LostBrain [lostbrain.com]

  • Some Line Lore (slightly OT) (Score:5)

    by Anonymous Coward on Tuesday April 04, 2000 @09:12PM (#1150791)

    It's been a while since I ordered lines (and that for radio broadcast use), but this should cover the basics: The important thing about the "dry pair" is that it is solid copper from one end to the other, with no intervening power supplies or electronics. They're sometimes called "alarm circuits" because they're most frequently used for burglar alarm (or other telemetry) where it's necessary to be able to tell if the line has been cut or shorted. (Applying constant DC and monitoring the current lets you do this easily. Yes, there are other ways, but this is old technology.) Dry pairs can usually be ordered between two points served by a single exchange, but they're almost impossible to come by if you're trying to get from one part of a metro area to another. (The telco would rather multiplex your service onto one of their wideband interexchange circuits.) In the case you're asking about (between your house and your neighbor) you should be able to get it. Hopefully you can talk the installer into doing the hookup at the neighborhood terminal block, rather than going all the way to the exchange and back. (Big performance difference!)

    One of the things that may be lurking on your line (and that used to give us fits when we were trying to set up remote broadcasts) is a "loading coil". These are put on long circuits to even out the audio frequency response, but unfortunately that means "even" for 10-15khz and below, and only if you're using ancient low-impedance equipment. You certainly don't want them there for digital use, but as they may be installed at intervals between the exchange and you, it's often difficult to convince the telco to remove them. (Short story: In one installation we were feeding audio to a transmitter site. All the available lines were in the same cable with 6 pair loaded and 4 unloaded. The telco first tried to put us on the loaded circuits, but we couldn't crank enough high frequencies out of them to make proof-of-performance standards. After a lot of arguing, we finally got them to move us over to the unloaded ones, which worked fine. Later on they moved the interexchange part of the circuit from a dedicated analog circuit to a channel on a T-1: Their mod/demod equipment added so much garbage that we finially gave up and put in a dedicated 2-hop microwave. Sigh!) Also in some areas you may not even be copper all the way back to your exchange. A number of companies are starting to install neighborhood boxes that do the copper to fiber conversion out on a pole or in a manhole somewhere near you.

    Other posters have noted that you may also run into problems with tariffs. Rates from the major telcos have the interesting wrinkle of charging different prices for different applications that use the same kind of circuits. If your company gets huffy, you may have to do some fast talking ("Sure it's an alarm... it's sending security telemetry from my house to my office!"). Whatever you do, don't mention anything about "computer networks" or "digital modems" :-) Also, be careful to watch your signal levels. Telcos tend to get pissed if a bunch of subscribers start calling up with complaints about your signal bleeding through on their phones.

    It looks to me like this guy's in about the best situation: He's served by a locally-owned small-town company with only one exchange building, and that doesn't mind him bending the rules (or may not even have any), and is willing to cooperate with his experimenting. Just don't think you can get similar cooperation from Ameritech or PacBell!

  • Re:CO-to-CO hops? (Score:5)

    by tzanger ( 1575 ) on Wednesday April 05, 2000 @06:27AM (#1150792) Homepage

    DSL connections do not work between COs for the simple reason that there is no unloaded copper between COs. Most COs are hooked together via frame clouds/ATM/SONET/what have you. Once the individual pairs hit a CO it's concentrated into your carrier lines: DS1-3 and piped either via a single copper/fiber/RF channel (usually copper but the new ones are all fiber I believe).

    24 phone lines can be carried in a single T1 line. That's were you get your 56k from. The DS1 spec is (simple form): 193 bits per frame, 1 for frame sync, the other 192 for 24 8-bit channels. 8000 frames per second gives you 8000*193 or 1544000 bits/sec, with 1536000 bits/sec actual useable data.

    Now about those 24 8-bit channels. They need to be encoded because you want to maintain a net 0 voltage on the line. so too many 1s or too many 0's gets you into trouble, not to mention confuses the clock recovery circuitry. Enter AMI. Alternate Mark Inversion just reversed the polarity of a '1' every other time it occurred. This still didn't solve the problem of too many 0s though, but with the 8kHz PCM modulated voice data it wasn't a problem because any kind of little noise would send an LSB to the '1' state and keep the clock recovery happy.

    (I'm a little hazy here, and I can't look up my old /. comment (about 6 months ago) that described this in eerily gory details, if someone can tell me how to search OLD OLD COMMENTS (not just stories) email me PLEASE!) Somewhere in the past B8ZS (Bit 8 Zero Set) came along and, with AMI, cleaned up everything. Basically if too many zeros were sent a '1' was injected with the same polarity as the last '1'. The clock recovery circuitry didn't care, but the data recovery circuit would notice that the mark had the same polarity and change it to a zero to keep everything 'right'.

    Anyway. To be able to put 24 phone conversations and have them all be kept track of properly, the telcos decided to band 12 of these frames together (12 frames, each with 24 channels) and use the LSB of each conversation for switching information. I believe it was the 6th and 12th frames of the Super Frame (SF) which carried this info, call them bit A and B.

    Bit A and B were the line status bits. They told the telco equipment whether each line was on-hook, off-hook, busy or ringing. Now with 8kHz PCM conversations going on, losing a bit 1/6 of the time meant nothing important and it was hardly missed. For data conversations though that reduced your 24 64k channels to 24 56k channels since the end modems have no idea when that bit will be lost. There's your limit to analog modems. ISDN gives you a 64k channel because the equipment doesn't screw with the data frames every 6th frame.

    Anyway the SF format was put away and the ExtendedSupaFormat (ESF) method was brought in. All it is is instead of using 12 193-bit frames, it uses 24 and continues the "I need the LSB of every channel every 6th frame" to give the telco 4 line status bits, A, B, C and D. The other two bits aren't used yet but it's for future expansion. They typically just mirror the A and B bits for now.

    T1 is actually both a Layer 1 and a Layer 2 spec. It originated from the old Bellcore D1 spec in the 60s and details both the actual line voltages and the framing of data to get to those line voltages. There are no such things as T2s and T3s, only DS2s and DS3s.

    quick summary:

    • DS0 - 64k channel
    • DS1 - (T1 data spec) - 24 DS0s with framing
    • DS2 - 4 DS1s with framing and filling
    • DS3 - 7 DS2s with framing and filling

    Now the DS2 framing gets REALLY weird because the DS1 lines feeding them are not likely to be in sync so there are variable fill rates and such to maintain an intermediate bit rate which isn't really standardized... it sits between 1.544mbps and 1.56mbps I believe and is tuned at each installation since the DS1s feeding the DS2s are more or less unique. Simiarly, the DS2s feeding the DS3 aren't necessarily in sync the DS3 too has an intermediate rate.

    Anyway the whole point of this post is to show that once you hit a CO you are no longer on your own copper pair. You are part of the collective. You are just a 64k channel (with an involuntary loss of 1 bit, thus dropping you to a 56k channel) in a sea of millions and millions of bits. And the fact that it all works pretty much flawlessly is a tribute to the Bellcore engineers.

    And no, I'm not a Bellcore engineer. :-)

  • Nominations For Geek Of The Year? (Score:5)

    by Hrunting ( 2191 ) on Tuesday April 04, 2000 @08:32PM (#1150793) Homepage
    Are they taking nominations yet? I'm not saying that this guy would or even should win, but he definitely should be nominated. Let me outline why (gives me a chance to use that fancy <ol> sign, too)
    1. Dedicated to his high-speed access
      Not many people would go through the lengths to get DSL that this guy did, especially considering his telco did tell them that they were planning on rolling out DSL in the future (just not the near-enough future).
    2. Dedicated to perfection
      Most people would've stopped after getting the first connection and been like, "Whoop! I rule!" but this guy actually tested out more equipment because, well, damn, that first DSL connection wasn't good enough.
    3. Donated efforts to local groups
      Granted, it's part of his work, but he took his understanding to the public and got them up and running as well. A geek is not selfish, nor is he greedy.
    4. Published
      This is most important. A true geek feels the need to let everyone know not just that he did it, but how he did it, in the sort of detail that allows it to be repeated by one and all.
    Kudos to this dude. He gets a nod for a nomination for geek of the year. Is there a beanie award for this? If not, there should be.

  • Some cautions in doing it yourself (Score:5)

    by psychos ( 2271 ) on Tuesday April 04, 2000 @08:08PM (#1150794)
    I've been using an SDSL connection between my office and house for the past two months. Paid $800 for a pair of Flowpoint 2200 routers, and BA takes $30/mo for the copper loop ($100 install).

    There are a few issues with doing it yourself. If there are are problems, you don't have an ISP to complain to. It can be difficult to track down if a problem is hardware related, in the copper loop, or in your own inside wiring. For the past two weeks, I had major problems (connection would develop massive packet loss and drop out at times), which I eventually figured out were the routers; just got them replaced yesterday after spending hours trying various possible fixes from Flowpoint. There are still some minor problems (had the routers randomly drop the link and reset on me once earlier tonight), so my next step is to redo all the inside wiring on both ends.

    As far as hardware recommendations go, despite the problems I would still recommend the Flowpoints. They can run in routed or bridged mode and you can do fun stuff like set up multiple ATM PVCs with traffic shaping, so one user's traffic doesn't disturb another's. (Here's another issue; with the line saturated, the latency jumps from 3ms to 140ms; I set up one PVC for my roommates and one for myself, and set them both to 95% traffic max to get around this...)

    At about 8500 feet, my SDSL runs at 1744kbit/sec; the max the Flowpoints will do is 2320 at shorter distances. Another option I looked at was the Netopia R7171; it wasn't out at the time (it should be now), but it'll do two bonded 1.5mbit/sec channels over a 2 pair loop, as opposed to a single pair for normal DSL.

    So basically, if you're not prepared to have to fix problems yourself, go with a commercial DSL company. Otherwise, if you have somewhere to stick the other end (office or whatever), this is a pretty cheap alternative to going through an ISP; I doubt I could find an ISP to give me a large IP block and controllable revdns for so cheap.

  • New? And a caveat.... (Score:5)

    by A. Lynch ( 17937 ) on Tuesday April 04, 2000 @07:36PM (#1150795) Journal
    We've been doing this at my company for quite some time now, just using different equipment.

    One of the main points to consider with this scheme is that the telco may be iffy on the use of an alarm pair for this use, especially if they offer their own DSL/Internet offering. We've been lucky so far, but we've heard reports of others trying this, and then getting shut down...

    Just for your info, we've used (with great success) the Expresso units from Tut Systems [tutsys.com] and the XL-12000 series (for the longer haul stuff), also from Tut. BTW- the Tut 12000 units do a full 2mbit. ;-)

  • Heh (Score:5)

    by Dr. Sp0ng ( 24354 ) <mspong.gmail@com> on Tuesday April 04, 2000 @07:31PM (#1150796) Homepage
    I wonder how long it's gonna be before the Slashdot Effect takes down the DSL line he worked so hard to wire up? :-)

  • Re:T1... (Score:5)

    by troutman ( 26963 ) on Tuesday April 04, 2000 @09:15PM (#1150797) Homepage
    FWIW, I believe you can also slap a CSU/DSU and router on each end and have a "T1".

    Yup, you sure can -- up to a limit of around 3500 feet, on 24 awg wire (at least, this has been my experience). If you use a heavier gauge of wire it will go further.

    Of course, DSL routers are much less expensive than a Cisco 1600 and CSU/DSU.

    True, but a new 1600 is overkill for something like a homebrew project anyway.

    You can get used T1 CSU/DSUs (no frills units) for about $200 on eBay often, and then get a pair of used old Cisco routers (like a CGS/MGS or even an IGS) for between $100-150 each. Total cost around $600-800, unless you happen to have some old T1 capable routers sitting around (you'd be surprised at the sort of equipment that is being pulled out of service and scraped these days).

    Yes, the older routers are not as fast, etc. etc. but for a simple end-point setup with a small number of users, even the 10 year old gear can keep up without any problems.

    If one was right near a telco CO, you could run a small/cheap/hobby limited range ISP operation this way -- pick up an old AGS+ with scads of serial and ethernet ports for maybe $400 for the central site. They can still pump a respectable amount of data -- the AGS+ was often used as the network core router for entire campus or corporate networks "back in the day" (like with 12 ethernet ports, 8 T1s, and two FDDI ports).

  • The GNU way (Score:5)

    by GMOL ( 122258 ) on Tuesday April 04, 2000 @08:22PM (#1150798)
    Do it yourself! It's the GNU way!

    Funny, I thought the GNU way was relying on people much smarter and harder working than oneself to produce software, without bothering to contribute working on open source projects of their own. Oh I forgot that I also thought the GNU way meant that you had to complain and whine about software that other people write and you don't pay for.

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