sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's extending PRI demarc

Hi newbie here. I'm ordering new PRI circuits from AT&T. They claim that they no longer extend the circuit to a smart jack in our phone room. The local telco's also decline to do it because it is an AT&T circuit. Our equipment vendor also declines. has anyone ran into this problem and how did you rectify it?
Thanks

We do it all the time on our systems and it's really pretty straight-forward. We just run a shielded category 5 cable, put a plug on one end and a jack at the other end. It's really supposed to be a "smart" jack, but a correctly-wired 568A or 568B connection will work just fine.

I have to tell you that if your vendor won't do it, then maybe you need another one. You may also just check for a local data network cabling company. Just tell them you want them to run a shielded category 5 cable run from point "A" to "B".

Ed, why the shielded cable? The circuit is just running across Cat 3 telco/house cable to that point anyway. Up here they just extend the circuit from the CSU on house tie cable.

I have seen the circuits run on house pairs BEFORE the circuit terminates on the telco's termination electronics, but on the output (conditioned) side of it, there are strict limits in the distance that the wiring can go. Usually, this limit is determined by the "line buildout" settings in the electronics. I was making the assumption that they have their electronics located in the basement where the wire run would be lengthy.

Typical T1 distance limitations from the smartjack are a little over 600 feet. 650 pops into my head, but that's probably lab conditions.

We typically use unshielded Cat 5, 568B on both ends, and rarely have trouble. I have seen instances where screened (foil around all 4 pairs) Cat 5 was needed, and even a rare circumstance where real, honest-to-goodness sheilded (each pair in its own shield) cable was required.

OK, so how would you know if you had cable problems between the "smart jack" and the telephone equipment?

Well, although the answer to your question would appear to be obvious, I see what you are saying. Obviously, a simple continuity tester would rule out any blatant wiring problems. I think what you are getting at though; it's those phantom problems that can occur and you want to rule out a wiring issue. Unfortunately, that's not quite as simple and would require the use of T1 test equipment to isolate.

It sounds scary and expensive, but I can honestly say that we have never (knock on wood)had problems with extended wiring we have installed for this purpose.

Run a Cat5 certification on your work. If it passes the wire map & bandwidth test, your link is good.

How far from the MPOE is your switch? You're probably not on the 50th floor of a building where the MPOE is in the basement. That said, some old house cable we had on a job was so bad that we ran new cat 5e from the 22nd floor to the MPOE.

Well actually the CLEC ordered the LEC to extend it to the suite and the LEC could not make it work on the house cable and we ran the cable and left it for him to terminate on both ends so he had that liability. That was a first out of probably a hundred T installs but it happened.

Who knows, but if it was a long run and you ran CAT 6 would that not have less loss?

Your Adtran Ace is designed to compensate for line loss, the dip switches are there but we have never needed to use them.

I spoke with a verizon t1 tech and he said you can get over 1000 feet easy if you seperate the transmit and recieve pairs away from each other.. this is what cuases the 600 feet limit..

I have extended T-1’s and PRI’s on cat3, cat5, cat5e, and cat5e shielded. I did however want to add to this thread that most cabling manufacturers make a specific cable for this application. If the customers are willing to pay, this is what we will always offer first, and in some instances (extensions over a few hundred feet,) it is all we will offer. Basically the cables designed for T-1 demarc extension have the pairs individually shielded. This fact is more important than the category of the cable.

Here is an example:
https://www.quabbin.com/finder/finder.cgi?cmd=display&cable_id=460

If the link does goes bad it is made by Quabbin...part number 9719

Also in Berk-Tek, part number 10032390

When T-1's were first being installed you had to use the shielded cable. I think that is now a thing of the past, at least as far as practice goes. I would have to agree that an extended DEMARC beyond a hundred feet or so, that it would be smart to use the shielded to cut down on electronic interference

I just got done running 50-pair for a 725' demarc extension yesterday. I need to extend the T-1, too (which will be a similar distance). What I'm gathering from this thread is that I can PROBABLY get away with CAT5E and perhaps some engineering inpur on the line buildout. Is this a correct assumption? Customer has been offered chance to use shielded cable and declined. I shouldn't have any unusual EMI issues on my cable path. Thanks.

Bill

That's quite a ways. Fortunately a T1 is more tolerant of low levels than hot, also a good CSU should have some gain you can build into it. If you've offered shielded and they declined, just make sure they are well aware that it may not work as expected. The shield was as much for keeping bleed over from the transmit receive path as for EMI, for that distance I'd sure push the shield.

Give the 50 pair a chance. Split the tx and rx between the bundles and don't forget to adjust the CSU line build-out. I'll assume you don't have a t-berd or other t1 tester so, have the service provider do a complete loop test to a CSU loop not just a 'hard loop' on the end of the wire pairs. A hard loop doubles the the length of the copper giving more line loss viewed by the tester. A 'head to head' test would be the best test but a 'soft loop' to the CSU should test fine.

Don't forget to see if the LEC tech will adjsut the LBO on the smartjack. Let us know what happens.

Just truned up a t1 from at&t that Verizon installed. Guess what, the trans and recieve were reversed from what they (verizon)told me. What a mess. They did the samething on the data t1. :bang:

T-1 extension came out to 740'; went live yesterday. So far, so good, but we'll wait until we get some traffic to call it good!

Thanks for the update. If you stressed it with no problem it should have no trouble carring traffic.
Bill