atcomsystems.ca/forum Forums VOIP Phones & IP PBX Networking DSL bridge cable pairs.

Verizon sold customer dsl service in (2) locations feed by bridge cable pairs via central office.

Customer wants DSL service at both locations which are on the same telephone number.

This would require 2 dsl modems at both locations.

I say it wont fly, because loop limits issue.
Can you have 2 modems with same address ?

I am confused.

It wont work, and i don't think its worth the time even trying it.

Ive never run across this issue, but common sense says no it will not work.

I am having some tense shift problems with this question. However I think it could work. The reason is the way DSL works. Each line must go thorugh a DSLAM card that puts the data on the copper loop. The DSL signal rides on the telephone circuit (copper loop) for part of its length and hops off again at the DSL modem before the end of the copper loop. If the lines are bridged upstream of the DSLAM cards in the central office, it should work.

CO Switch - DSLAM ===== DSL Modem - Phone

In this actual, unretouched photo, a "-" represents a copper loop carrying just voice, while "=" represents the part of a copper loop carrying voice plus data.

If the DSL signal hops off when it reaches the first DSL modem how will the second modem get a signal?

From another DSLAM. Due to the fact that this site doesn't allow more than one blank space, I couldn't really draw it. Here's another try.

CO Switch
|
|-DSLAM========DSL Modem - Phone
|
|-DSLAM========DSL Modem - Phone

If it's bridged at the CO the full signal should get to both locations. Would Verizon allow two different customer modems on the same CO DSL equipment is the question. If they do there is no reason it shouldn't work.

This could be one of those scenarios that work in theory but let's hope the dsl connection isn't important to this business cause the gremlins I have sitting on my shoulder a screaming jikky as loud as they can. They are laughing too, or maybe it's just a snicker. Anyway, get back with us after you take it for a test drive.

I know in my neighborhood when they put DSL in, the first thing they did was take out ALL the bridge taps. I was told that they added too much "something" (capacitance? resistance?) that hosed up the DSL signal and dropped power dramatically on the circuit.

Sam

Yes Sam, only a CO bridge will give a balanced circuit, bridging in the field wouldn't. I just can't see any Telecom allowing multiple modems on a dedicated DSL service.

DSL just "rides" along a copper cable pair. One side of the pair can actually be open and DSL will still work. The copper pair is more of an "antenna" as far as DSL is concerned.

We aren't talking about phone numbers here. Everybody knows that a full copper loop is required for a POTS line to work. We are talking about the possibility of getting one-half of a copper pair to the customer premise. If that can be accomplished, then DSL will work even if the associated voice circuit is dead.

Remember, as Grim illustrated, you have T/R going into the DSLAM in the CO for a particular POTS line. Both the POTS and DSL signals ride the copper pair to the premises. At that point, DSL filters chop out the DSL signal that was inserted by the DSLAM in the CO, so every device except the DSL modem must have one of them..

That same phone number can be sent through multiple ports on the DSLAM in the CO. The DSLAM doesn't care what phone number is riding on the cable pairs. It's just hitching a ride for a clean metallic path to the DSL modem. That same phone number can go out to 10 locations (hypothetically) and still have separate DSL accounts and modems working on them. Remember, DSL is just hitch hiking on an existing copper circuit. It's not picky.

It's really so simple that it looks complicated.

Good point, Ed.

Sam

Simple. It may be the same telephone number at both locations but the DSL is not bridged. Both locations originate at the CO so I doubt even the POTS is bridged. This can be considered as two separate accounts even though the same number goes to both.

Would you be able to connect two DSL modems, say with a bridging adapter at a jack? No.

-Hal

I've got it now, that makes sense. Thanks Ed.

This is follow up to original post on 12-19-2007.

The Installation was a success.
Thanks to all whom posted on the issue.

Have a great holiday, and please be safe.

I'm probably looking at this the wrong way, but why is the customer asking for the same phone number? Is it just for billing/id purposes?
I assume that these are regular CO circuits with a voice part that has dialtone and the modems are some kind of ADSL.

It is same number both location, as it is a opx.
(off premise extension)

Gotcha, thanks. Looking at the topic title I thought that this had to do with the creation of a bridged DSL subnet. Reading the responses, I realized I was wrong somewhere.

Sorry to resurrect this old post but it is exactly what my father wants to do (he just asked me today). He has his house which is about 2 hundred yards away from his shop and he wants Internet access at his shop. He has a off premises extension in his shop (same phone number as his house and his house already has DSL). I would like to research this option but don't know quite what to ask for. Is there something special that the phone company would need to do to put a modem at each location?

Brent if you read the whole thread above you will find that it is possible but that you may end up paying for 2 DSL accounts if all you dad wants in Internet access in the shop you should consider WiFi
If you want further discussion on this I suggest you start a new thread so that everyone knows what your requirements are.

You would be better of Brent to setup a wireless network connection between those two points, especially if you have a line of sight somewhere between them.

A couple of wireless routers, some cable, maybe some enclosures.

Still a hell of alot cheaper over just a year than paying for 2 DSL connections.

or move the modem to the shop when he needs it out there

And it continues to amaze me to have NDT but DSL works fine!!!

Dial tone has nothing to do with DSL. Just need a one pair copper in good condition.

A dry loop (DSL line with no voice service) still has voltage on it, that is how the signal maintains its integrity. The DT just isn't there.

I was surprised the first time I toned on a dry loop and got a light on my toner (don't tone live lines, they tell me). They look the same as a normal line to a buttset voltage check too.

A dry loop (DSL line with no voice service) still has voltage on it, that is how the signal maintains its integrity.

Actually battery is there (so it's not a dry loop) so that the wire maintains it's integrity and also so that techs can know it's a working pair. Battery is not necessary for the DSL.

-Hal

Yep, had a fax with DSL on it stop working...NDT but the DSL worked great...open HC in the CO...across the street. Who'd a thought???

:shrug: