What's going on with my phone and DSL wiring?


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Old 03-17-13, 01:01 PM
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What's going on with my phone and DSL wiring?

Hi,

I am trying to figure out how my phone and DSL is wired at my house.

See the attached picture. It might be a little hard to tell, but the only wires used in the CAT5 cable (to DSL modem) are the blues.

The AT&T installer added a dedicated line to go to the DSL modem, to avoid problems with internal phone lines. In the box outside, my phone line is connected to the green/red. The other cable for the DSL is connected to the yellow/black. I don't know if that is actually a 'second line'. I don't have a second phone line subscription. It may be that the yellow/black is just being used to connect to green/red via some splitter (see top of picture)?

The curious thing to me is that if I plug the line feeding the DSL modem into my phone, I get no dial tone. I thought it should have a dial tone.

Also, if I connect my house phone wire to the cable to the DSL modem, the modem stops working. I am guessing it is because i have noise on my house phone line circuit due to a non-outdoor rated wire run under concrete to my shop, which is in a conduit that is likely holding water (so grounding the phone wire, and causing a buzz).

So, why no dial tone on the line feeding the DSL modem?

Thanks.
 
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Old 03-17-13, 01:53 PM
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Welcome to the forums.

You only have one active pair of wires in use from the phone company. The DSL is wired directly to that pair. The phones go thru a filter and then to that same pair.

You won't here anything because DSL is not an audio type signal. If you connect a phone into the DSL line you will create a short and kill the DSL signal.

If you are trying to wire to a different area (like your shop)..... you would connect the shop wires to red and green and then put a DSL filter at your shop phone. Otherwise your shop phone will create a short on the line that will kill the DSL.
 
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Old 03-17-13, 02:43 PM
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In addition, you are only looking at YOUR half of the interface. The Phone Co side is inside the enclosure to the left. But as PJ said there is only one active line in your house. I don't see anything attached to the yellow/black pair in your interface box.
 
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Old 03-17-13, 06:56 PM
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Thanks for the info. Just to clarify the picture, the gray cable with the red/green goes into the house for the phone. The beige one goes to the DSL modem, and, as said before, has no dial tone.

My assumption has been that, since I have one line, both the phone and DSL come in on that line. Then each phone needs a filter. I hadn't heard that connecting a phone without a filter would kill the DSL. I thought it would just cause noise in the phone.

Ultimately, what I need to do is get my new phone wiring going for the DSL and phones. I have run Cat5e throughout the house, temporarily just connected to the existing wires inside the house. The main Cat5 cable from the NID goes to a central closet, where I make the connections to the other lines in the house.

If it is true that both signals (phone and DSL) are on my single house line, I don't understand why I don't get DSL via the phone line in the house if I plug that into the DSL modem.

To simplify this, perhaps, shouldn't I be able to plug the DSL modem straight to the existing phone line configured as normal, and have it work?

Thanks.
 
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Old 03-17-13, 07:01 PM
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Perhaps I just need to run an extra Cat5e from the NID to my comm closet, dedicated to the DSL. That should solve it regardless, I think.
 
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Old 03-18-13, 03:31 AM
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I don't see the need in the extra wiring from the NID just for DSL. If you filter all your phones, fax machines, satellite connections, etc. you should be able to plug your modem into a phone jack without problems.
 
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Old 03-18-13, 10:20 AM
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Originally Posted by PJmax
Welcome to the forums.

You only have one active pair of wires in use from the phone company. The DSL is wired directly to that pair. The phones go thru a filter and then to that same pair.

You won't here anything because DSL is not an audio type signal. If you connect a phone into the DSL line you will create a short and kill the DSL signal.

If you are trying to wire to a different area (like your shop)..... you would connect the shop wires to red and green and then put a DSL filter at your shop phone. Otherwise your shop phone will create a short on the line that will kill the DSL.
That's not true. DSL is simply a superaudible signal that rides over the same copper as the phones. DSL filters do not 'separate' the DSL and phone signals, they simply strip the DSL signal off the jacks that have phones plugged into them - otherwise you would hear the hissing noise of the DSL. You can plug a DSL modem into any phone jack on the line and it will work. A phone plugged into the DSL side of a filter/splitter will NOT short out the line OR kill the DSL, because the signals are meant to coexist (in fact at the very beginning, there were no such thing as filters/splitters - they were developed because people complained of the hissing noise).

Larry: The reason there is a separate CAT5 line run is because aside from (the gray cable) being low quality sub-cat3, the original jacks are probably run in a daisy-chain. It's an ok configuration for voice, but it introduces interference that causes DSL speeds to drop. DSL is such a crappy technology to begin with that you have to give it the best chance - ie: a home run with Cat5 from the modem straight to the NID.

I can't see clearly, but the demarc module that has the RJ14 jack and two wiring taps is most likely a DSL splitter (not to be confused with a filter).. Basically it strips the DSL signal off right there and routes it to the DSL modem so you do not need individual filters at each phone - and so that problems on the voice line (like your ground fault) do not interfere with the DSL. That would explain why the modem will not connect when plugged into your voice jacks and why you do not have a dialtone at the DSL jack.

I'm not sure what the topmost module is for though, I've never seen that before.
 

Last edited by JerseyMatt; 03-18-13 at 10:35 AM.
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Old 03-18-13, 10:46 AM
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Oh yeah, I forgot about your original question..

When you bring the new Cat5 out to the NID, you want to keep the current configuration with the splitter. That gives you the best possible signal. What you can do if you don't want the extra dedicated cable going up the side of the house to the modem is use one of the extra pairs in the new cable.

This will sound a bit confusing, but it's how you have to do it..

Remove both existing cables from the terminals on the splitter
Connect the BLUE pair from the new cable to where the red/green used to be
Connect the BROWN pair from the new cable to where the blue/white used to be
Save the ORANGE and GREEN pairs in case you want to add extra lines later. Wrap them back around the cable jacket neatly.

Inside at the closet (Ideally you will use a punch-down block here):
Connect the BLUE pairs of all of your VOICE jacks to the BLUE pair from the NID.
Connect the BLUE pair from the DSL modem jack to the BROWN pair from the NID.
 
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Old 03-18-13, 11:54 AM
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I'll have to admit (but didn't want to state here as an expert), I ran a separate pair to my modem from the NID, mainly because what you mentioned. I didn't know it at the time, but since all my phones were daisy chained, I just figured there would be more "load" or noise on the lines, so I ran the dedicated filtered pair. Glad I did something right.
 
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Old 03-18-13, 12:20 PM
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Thanks JerseyMatt. That's the way I thought it was working regarding the two signals on the one line. And your saying that the DSL is split from the phone signal at the NID makes sense also. I can simply run my Cat5 out through the hole in the wall and connect as you suggested. I do have punch down connections in my connection closet.

Thanks.
Clay
 
 

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