DSL problem and solution

[mdshunk]

Had a weird DSL problem today, that I managed to solve. I thought I'd pass along the story, since more and more regular electricians are working on this stuff.

Tenant in a commercial building was moving from one office to another in the same complex. Just three lines. Two voice, and one DSL which they also used for their fax and credit card machine. In the phone room, I found their old station cables, the accompanying cross connects wires, and pulled the cross connects. Their new space has a 6-pair going to it. I punched down their three cross-connects to the first three pairs of the 6-pair going to their new space.

Their new space actually has a NID installed in it (weird, eh?). I hooked the appropriate station cables in their new space to the first three pairs of that 6-pair on the NID, called the ANI at each jack to confirm proper operation, and went on to the next job.

Not two hours later, they call (frantic), saying the DSL doesn't work. I came right back, discovered dial tone on the DSL line, but the DSL modem had neither the DSL light or the Internet light lit. What could it be? I was really racking my brain. The only thing I thought it could possibly be was the carbon arrestor in the NID that was in their space. I pulled that pair off the carbon arrestor, and connected it with UR connectors directly to the station cables, completely bypassing the NID and the accompanying carbon arrestor.

I'm not sure what was wrong with this carbon arrestor (maybe nothing?) that it would pass clear dial tone but mess up DSL, but that did the trick. Just passing this along in case this happens to someone else. I'd still like to know why bypassing the carbon arrestor let the DSL connect.

[peter d]

May I ask what an NID is so this makes some sense to me and others who might have no clue what you're talking about?

[mdshunk]

May I ask what an NID is so this makes some sense to me and others who might have no clue what you're talking about?

http://www.dslretorts.com/Paladin/images/NewNID.gif

[mdshunk]

ANI is automatic number identification, if that was your next question. :wink:

[iwire]

Had a weird DSL problem today, that I managed to solve. I thought I'd pass along the story, since more and more regular electricians are working on this stuff.

I could not help but chuckle when I read that, that makes you an irregular electrician.:D

[Kdog76]

So NID is the demarcation point?

[mdshunk]

I could not help but chuckle when I read that, that makes you an irregular electrician.:D
Yes, I'll absolutely go along with that. :D No, I'm just a regular electrician passing along information to other regular electricians. The real phone guys probably already know what I did wrong.

[mdshunk]

So NID is the demarcation point?
Normally, which is why I was surprised to see it used instead of a punchdown block in a suite in an office building. If I was to guess, I'd guess that when it was installed originally, the phone guy dispatched was an "outside guy", and that was what was on his truck. The phone room already had a couple really nice 50 pair Cook blocks, so the arrestors were redundant.

[peter d]

http://www.dslretorts.com/Paladin/images/NewNID.gif

Now if you had just said "demarc" all of that would have made perfect sense to me. ;)

[iwire]

Now if you had just said "demarc" all of that would have made perfect sense to me. ;)


NID stands for Network Interface Device. It is also sometimes called a MPOE, Minimum Point of Entry. All of the phone jacks in your house end up at the NID. The NID box is usually located outside of your house on the side but is sometimes in a closet (usually for businesses) or in a basement. The NID hands off the phone service to the phone lines outside of your house.


http://maxolasersquad.com/network/opennid.jpg

[mdshunk]

The demarc is a place. The NID is a piece of hardware, most often used at the demarc. I was surprised to find it used with inside cabling. Go Sprint!

[Kdog76]

The demarc is a place. The NID is a piece of hardware, most often used at the demarc. I was surprised to find it used with inside cabling. Go Sprint!

:-? I guess that's why I'm a REGULAR electrician.:D

[mdshunk]

:-? I guess that's why I'm a REGULAR electrician.:D

demarc is the point of demarcation. The NID is the hardware installed at the point of demarcation.

[tom baker]

The carbons can create a slightly conductive path to ground. OK on analog, but not so with digital. Carbons are intended for lightning protection, and are not used any more as they can fail. I have about 30 remote sites with carbons, replaced all the carbons with gas tubes...they go into same protector.

[mdshunk]

The carbons can create a slightly conductive path to ground. OK on analog, but not so with digital. Carbons are intended for lightning protection, and are not used any more as they can fail. I have about 30 remote sites with carbons, replaced all the carbons with gas tubes...they go into same protector.
There's my answer. Thanks Tom!

[FlyFish]

I had a similar type of trouble where the DSL kept dropping off. I tried new filters, new modems and finally found the trouble to be in the NID. I found the spare screws (red and green) not tight. Although the screws that had the inside wires were tight the spare screws being loose created a bad connection. Both sets of screws need to be tight even without wires on them. Continuity is from one screw to the other with a little copper strap.

[iwire]

Both sets of screws need to be tight even without wires on them. Continuity is from one screw to the other with a little copper strap.

Kudos to you for noticing it, that could have gone on for a long time.

[FlyFish]

Kudos to you for noticing it, that could have gone on for a long time.

It did... Took me 4 visits.

[smo]

Some of those NID's have built in DSL filters in them, allowing the inbound line to be split into "voice" and "data" pairs, so you don't have to filter each voice jack on the premises. Is it possible the one you worked on had a built in DSL filter?

(BTW - sometimes the filter is located in the "tamper resistant" side of the NID, which you need a "security hex" wrench to open.

[mdshunk]

Some of those NID's have built in DSL filters in them, allowing the inbound line to be split into "voice" and "data" pairs, so you don't have to filter each voice jack on the premises. Is it possible the one you worked on had a built in DSL filter?

(BTW - sometimes the filter is located in the "tamper resistant" side of the NID, which you need a "security hex" wrench to open.

no... I actually checked that on the orininal MAC work.

[kbsparky]

Another term for the NID is SNI. :D

Just in case you weren't confused enough. :rolleyes:

[mdshunk]

subscriber network interface?

[kbsparky]

Probably .... :rolleyes:

It was an older term that I've heard over 20 years ago, when they were first starting to use the interface jacks. Some of the first ones we installed were indoors, usually at the first jack.

[hbiss]

The only thing I thought it could possibly be was the carbon arrestor in the NID that was in their space.

If it was the same type NID that you have pictured it does not contain carbons, the protectors would be either solid state or gas tube. Those NIDs sometimes do contain a half ringer for the purpose of line testing which is always bridged actoss the line. Apparently there was a problem with the protector mod for that line. Since it was the DEMARC you should not have done what you did but rather called in a trouble ticket, panicked customer or not. Wasn't your problem, tell them to deal with it.

Sometimes being a telephone tech has it's benefits.

-Hal

[LarryFine]

Now if you had just said "demarc" all of that would have made perfect sense to me. ;)But, if Marc said demarc, he would disappear. :grin:


Like when someone asked Descartes if he wanted some tea, and he answered "I think not." *POOF!*

[mdshunk]

Since it was the DEMARC you should not have done what you did but rather called in a trouble ticket, panicked customer or not. Wasn't your problem, tell them to deal with it. Hal, it wasn't the demarc, which was part of what I was trying to explain. The demarc was in the phone room, right after the Cook block. This was just a NID, used on the end of a 6-pair radial cable coming from the phone room. Someone used a NID instead of a punchdown block. It was customer owned cabling, but it was probably originally installed by the phone company.

[peter d]

But, if Marc said demarc, he would disappear. :grin:

You're a funny guy Larry. :)

[Security101]

subscriber network interface?

You are correct, Marc...

Jim

[hbiss]

Someone used a NID instead of a punchdown block. It was customer owned cabling, but it was probably originally installed by the phone company.

Ahh, well in that case I would have just removed the whole damn thing and replaced it with a split 66M block with bridging clips. Much easier to connect your wiring to, no? I hate those binding post screws though the newer ones use a "no tools required" lever.

-Hal

[mdshunk]

Ahh, well in that case I would have just removed the whole damn thing and replaced it with a split 66M block with bridging clips.
I thought about it, but I didn't have one. To get to it, I had to go through the ceiling and sit on a platform on top of the bathrooms. A couple UR connectors solved the problem. Truthfully, I wasn't sure what the problem was at first, so jumpering around the arrester with UR connectors was just a lucky guess. I have no tools to test the quality or presence of a DSL signal.

At Bob Badger's suggestion, I just bought a cheap DSL model off eBay. It's about the size of a deck of cards. It hasn't arrived yet, but I'm going to tape a few 9volt batteries to the side to make it portable, and use it as a DSL connection detector.

[iwire]

At Bob Badger's suggestion, I just bought a cheap DSL model off eBay.

I think that was Mark (e57) I am not that helpful. :D

[mdshunk]

I think that was Mark (e57) I am not that helpful. :D
Yeah, but I never really liked e57 that much, so I'm giving you credit instead.

[hbiss]

I have no tools to test the quality or presence of a DSL signal.

Most of us don't. Normally you would use the customer's modem to see if it links up. If it doesn't I check my wiring and filters (if necessary) in the right place then call tech support, same as for any other issues. They are capable of diagnosing any problems remotely and will tell you what to do. Normally that's the customer's responsibility or their geeks.

I'm not sure you can use just any modem beyond checking for linkup because of a modem's ESN. If the account has already been established it will only work with the customer's modem.

Beyond seeing that it links up I usually don't get involved, although I have set up new accounts for some customers. Many DSL providers require reprovisioning of the modem and router to work with each other if you are going to connect to a network with more than one computer. You can't just plug a router into a DSL modem like you can with a cable modem.

-Hal

[LarryFine]

Yeah, but I never really liked e57 that much, so I'm giving you credit instead.This place is becoming more like a reality TV show every day! :roll: (:D)