Make Your Own DSL

Logic Bomb writes: "Robert Cringley's latest is a striking set of instructions on how to create your own DSL service, or even your own "socialist Internet Service Provider". A cookie goes to whomever manages to implement this first! :-D" Cringley is on a roll.

Tried to Order one of these ckt's

[bruceg]

I tried to order one of these circuits about three months ago, and apparantly the telco's are on to this. I wanted to connect two buildings, so I tried ordering a "dry pair" from Verizon, and they said they didn't do those anymore.

I ended up ordering a PtP T1, which is only going to increase the cost of replacing the aging 56k circuit, now connecting the two buildings, by $110. Not bad considering the increase in bandwidth.

Re:um, yeah, whatever

[DeadPrez]

One thing you have to remember is most T-1, DSL, etc contracts specifically state you can not resell bandwidth. If you were going to do this you better make sure whatever you use for your uplink legally lets you resell bandwidth (99% of the time its going to be illegal).

WHOA! Cringely Got It Right! BUT........

[darkPHi3er]

Cringely got it right, in my last business, the area was out of dedicated "Data Lines", so PB had to send out an install tech who really knew what he was doing, i was looking over his shoulder and noticed that he was using our alarm lines...the tech told me almost exactly the same story as Cringely, including that if you called PB and asked for a pair of "guard lines" you'd be told they didn't exist or that they were all assigned in your area.

SOME THINGS TO NOTE:
since this is a point-to-point connection, your throughput will vary with the quality of your wire pairs

you might also need to perform line balancing, as some of these wire have been in the ground/air for a LONG time

if you have big power transformers or other "leaky" devices near your wires, your S/N ratio could be terrible

AND, LAST BUT NOT LEAST, anyone can just simply t-splice your line to get 100% access to your communications, with maybe just having to perform a simple impedence adjustment...

BUT, still cool for all of that BTW, when "Boardwatch Magazine" still had Jack Richards they ran a very similar (but more detailed) piece on this about 3 years ago

Peace, Love to my Homies

Re: DSL over Dry Copper - already done

[ennuiner]

Yup, even Slashdot has covered it before [slashdot.org]. I guess its novel 'cause Cringely's talking about it tho.

Old news, here's here's why you don't do this

[Kagato]

The alarm line trick as been around for ages. Usually using the line to cross connect a CSU/DSU like it was a frame circuit. The problem isn't technology, it's quality. High speed datacomm expects certain line quality in order to do what it needs to do. Things like quality of the line, minium data throughput, etc are all defined in the tariff. Problem with these types of lines is that the tariff basically says the line should pass a simple continuity test and that's it. Afterall, that's all an alarm needs. So, if you get a real noisy line, you're sunk.

As an experiment that's fine, but don't let a business depend on this because you'll have no recourse with the Telco.

Re:Bandwith without connectivity is worthless

[steevo.com]

While the dry pair does go through the CO, it can be connected to another dry pair to another location at the CO.

Check your local PUC for the tarriffs, and see if this is a mandated service. (It probably is.) If the phone company tells you that they can't do it, show them the tarriff. If it's tarriffed, THEY HAVE TO SUPPLY IT.

There is a bunch of cool stuff you can do... Within the city WAN's for cheap or maybe split the cost off Internet T1 bandwidth with another company, etc.

Re:There is a reason They don't like this

[sks]

I'm reasonably sure that it's the reverse of what you state- the T-1 interferes with the DSL. T-1 is "high power" - there's real voltage running down a T-1 pair, and if there's a T-1 circuit in a bundle, that renders that bundle unfit for DSL.

Mod this up please

[Anonymous Coward]

I have done this before. I work for Cisco.

If you can get a dry pair from the telco company you are in business. You need not be within 18000 feet but you will get less throughput if you can't find a way to put more voltage on the line.

Get you dry pair to where ever. If it goes to someone who has an internet connection assign youself an ip address of of their subnet and voila done.

WANT MORE ?

run a pair to your buddys house, either you or your buddy needs to get a cable modem. Put a NAT router on cable modem like a linksys, a netgear 311 or 314 or a cisco 806. Then attach the ethernet side of the dsl modem onto the switch/hub containing the connection from the router. Set the router up to do DHCP or do static assignments.

You can even set up ports to forward to internal servers and stuff like that so you can host game servers, mail, whatever.

DSL, SDSL, HDSL etcDSL are all layer two technologies. This means that it is pretty much like stringing a cable down to your buddies house.

The differences are:

1. The Data is slower than eithernet
2. The distance limitation of ethernet is removed.

Thats it.

You can also do this with dark fiber. You can get really huge, fast pipes on fiber.

You should always check the possibility of dark fiber or dry pairs when you provision bandwidth. Read the above sentence again. Otherwise you are just blithely going to the telco and wasting your money.

Re:what a bunch of bull

[Tim Doran]

I work at a phone company (a big, big one, with an ampersand in the name) and this is absolutely not BS.

In fact, we're now selling voice services over dry pair lines using DSL. If we can do it, you certainly can. As long as you don't give up before you even start...

Re:um, yeah, whatever

[sapphire42]

Actually this DOES have uses. We have a client
right now that wanted two buildings connected so
that they could share info, but didn't want that
info to be accessible on the internet at all.
We ran an alarm circuit between the two buildings,
plugged in a box on each side, and got a 2 meg
circuit up between them. Yes, there are lots of
uses for this. Not *everything* needs to be about
the *internet*, sometimes it's just about sharing information.

Reposted from Macslash

[belgar]

I just spent some time talking to a friend about this article who is a telecom engineer, and he told me some interesting things about the dry-pair concept:

Folks have used dry pairs for a long time to get cheap premise-to-premise extension service, always-on for dummy terminal, and low-ball PBX to offices in the same CO serving area. Compared to a full T1, this can save you a lot of money, especially compared to what it can cost for a conditioned T1.

However, an important caveat to keep in mind is that nothing at all has been done to condition the pair for higher data rates, since all that dry-pair is rated for is low-quality voice or very slow data (300 bps). In theory, new telephone twisted pair is designed for about 2 MHz bandwidth. If we assume a new dry pair in excellent condition, and you apply the bandwidth formula which includes distance, you can exceed 50 Mbps under 2,000 feet. At 20,000 feet, you can reach 1.6 Mbps. Note these are maximums and do not assume significant disturbers, such as existence of ISDN pairs, other T1 pairs, or nearby RF interference. Typically, only one traditional data pair is allowed per binder group due to the crosstalk artifacts, as the data transmission is symmetrical.

Anyway, the killer is that the line is unconditioned, and it can be awesome, or it can really suck. We have two runs through the local school board of unconditioned twisted pair, and one gets 1.1Mbps, and the other gets 56K, so it's pretty much a crap shoot every time as to whether you're going to get a good line, or a crappy one.

The Real Scoop

[drwho]

OK, I haven't the patience to read ALL of the comments on this article, because many of you are posting complete crap.

First, this is NOT BS. It MAY really work (see below). Second, if this is over your head, go read MSNBC or shut up. Slashdot is techie oriented and you either enjoy, ignore, or go elsewhere.

Third, this has been done before. However, ILECs (big, bad old Bells and their similars) heard about this and decided that an alarm circuit was NOT the same as a dry pair - they started putting filters on them so people couldn't run them as T1 circuits. This is what I heard several years ago before DSL became popular - and this may not be entirely true. I heard this from a Bell guy and they routinely lie, out of habit. So Crigley is not inventing anything new here, but is merely popularizing it. And I see nothing wrong with that, except:

Fourth: On a mailing list I am on, this URL was posted. A Cisco Jock, with many years of ISP/NSP experience, said that anyone doing this could get into big trouble if this 'alarm circuit' was causing trouble as it was being used inappropriately, and could be socked with $10K in costs and lose the line. I noticed an anonymous coward posting something similar, above, I wonder if it was the same guy -- anyone with specifics please respond.

So, if in spite of all this, you want to proceed, let me give you more info (and enough rope to hang yourself with, perhaps): ILECs are required by tariffs to offer certain services at certain prices. Some of these, they don't want to offer but have to, if the customer asks. However, customer service representatives seem to be trained NOT to help you if you don't know EXACTLY what the OFFICIAL name of the service is. These are called "non-marketed services". You must know the proper name, which varies from state to state. For instance, most people don't know about call-forward-busy available in massachusetts for only $1/mo -- because it isn't marketed (also note that you have to pay a service charge each time you want to change the number forwarded too!). If you're really interested, go get a copy of the ILEC's tarriff from the appropriate state agency. I keep on meaning to, but have never got around to it.

If it wasn't for the caveats mentioned above, this would be a great idea. I have been playing with the radio based wireless stuff for a long time now (guerrilla.net) and I know that it's not reliable, high speed, and over a decent distance all at the same time (I'd say "pick two", but you might not even get 2 of 3!). But until we have addressed the issues mentioned above, this may not be a good idea.

Look for a future article on guerrilla.net on this, once we have sorted the facts out and investigated urban myths.

Re:WHOA! ... a few more things...

[rtfm]

i used to work at an isp where dsl was no where in the near future for our customers, only because of the practices of the local phone company (read baby bell). anyway... you may also want to check in what is sometimes refered to as a BANE circuit (i believe) as this is another name for the alarm circuits.

one last thing to keep in mind: if the phone company has a load coil on that pair that you plan on using, your dreams have just been killed. sorry.

either way, some new equipment is starting to surface which brings some new ideas to the table for lines like this such as hdsl2 (search on google, you'll like it ;) ) basically hdsl over a single pair, with increased distances.

i have to say tho, the idea of moving into the old alarm company's building is a good one, too bad there weren't any around really where we were looking to do this.