atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's New T1 installation question

Hello Everyone, I have a question. A company has asked me to wire there new T1 installation from the grey box outside to the Cisco router inside. I am very familiar with LAN networking, but lack the teleco knowledge for this wiring. The T1 box appears to have 2 sets of 8 wire connected. And according to the paperwork, they going to use line 1. I didn't see offhand a RJ48 type recepticle in the gray box. So what would be the best way to wire from outside to inside? I did see they supplied 1 RJ48 connector with rubber inserts for wires 1,2,4 and 5. I should be able to wire to the posts outside using cat 5 (under 100ft) to the RJ48 correct?

Or do I need to supply more info for better assistance? And is there a specific wire number scheme on the outside? (ie...top row from left to right is 1-4.., then 5-8 for bottom row, plus there is another set of 8 wires below that won't be used)

thanks everyone, any help would be great.

I'm not really visualizing the box you're talking about, but 1,2,4,5 is the pin out for an RJ 48X. (2,1 = Receive T&R; 5,4 =Transmit T&R)

I never liked using Cat5 for anything over 40' and usually preferred not to use it all for anything but perhaps a patch cord. If it's under 100' you could try it. Do you have a T-1 test set (Sunset, T-Berd etc) to verify that your run is good and not taking any errors?

For a run like this I would recommend 2 runs of shielded Cat 3, with one pair from one cable supplying the Transmit pair and one pair from the other cable supplying the receive.

Sam

The T1 box outside has a closed off side (left) and 8 lines coming from it and connecting on the right (with RJ48)each of the 8 connections has a post to screw wire onto. And there are 2 of these 8 wire setups installed in the box.

From what I am reading, alot of times this is wired to a smart jack box. Where then I would just plug the supplied grey cable from it to the Cisco router. But this person opted to do his own inside wiring and doesnt have anything but the outside T1 box. And I wanted to help him out with this.

I understand about running the 2 CAT 3 cables. Would I then run that to say a punch down block. From there, whats the best way to run it to the router? just a short patch cable with a punch down lines on one end, and the RJ48 connector on the router side?

And no, i do not have a T1 test kit.

Whew… Like Sam I’m really having difficulty getting a visial image of what you’re working with… I had to break your post down in bites to see what I could come up with for assistance.


A company has asked me to wire there new T1 installation from the grey box outside to the Cisco router inside.

Demarc extension, groovy… We can do that ‘round here. …. “Grey box outside” where the entrance cables from the Telco terminate, just to be sure we’re talking about the same thing.


The T1 box appears to have 2 sets of 8 wire connected. And according to the paperwork, they going to use line 1.

“T1 box.” The Network Interface Device (NID … or aka Smart Jack) …. Two sets of eight wires connected? … Ummm, from/to where are the 2 sets of wires connected?

“Line 1?” Is this thing look like it’s a two-slot housing, that could terminate 2 T1’s?

I didn't see offhand a RJ48 type recepticle in the gray box. So what would be the best way to wire from outside to inside? I did see they supplied 1 RJ48 connector with rubber inserts for wires 1,2,4 and 5.

Whuh? …. You said there was a “T1 box” a SmartJack, right?… The RJ-48 (x or c) “should” be on the bottom side of THAT, not in the “grey box.”


I should be able to wire to the posts outside using cat 5 (under 100ft) to the RJ48 correct?

If you NEED to yes. Cat5 will work. … I’d like two Cat 3 shieldeds like Sam said but under 100 ft, Cat 5 should do fine.

Or do I need to supply more info for better assistance?

Yeah, me thinks so… but see what you think after you read all this! LOL

And is there a specific wire number scheme on the outside? (ie...top row from left to right is 1-4.., then 5-8 for bottom row, plus there is another set of 8 wires below that won't be used)

I’m puzzled even to what you’re looking at with this….

Ahhhhh are you interchanging the term "t1 box" and "grey box outside" ... With that decription now, most everyone out here knows what you’re talkin’ ‘bout.

Sorry for all the confusion. I just do not know some of the proper terms for this equiptment. But I have been researching. lol.

The "Grey Box" or "T1 box" as I called them is the T1 demarc. as in the picture here.

Picture is not actual photo, just one I found that looks to be really close. But now i see how my explanation was not really exact..lol. I was working from memory. which isnt too good i quess.



So whats the best way to get from here...to the router? I do appreciate you guys putting up with me for sure..LOL.

Does your NID look like this?

Marc, I hope that it looks BETTER than that....pretty sloppy IMO.

yes, your NID is pretty much what his box looks like. only difference is the right side looks more like the picture I posted. which could just be a newer box i recon. But I will have to take anothe look in the morning to be sure. Now that you guys have given me more information to work with.

Marc:

I'm sure that is the NIS that the OP has. Those are pretty much the norm these days.

Crawfish:

Just wire the distant jack at the router as 568B and connect the white/blue of your cable to the red/green terminals. Connect the white/orange to black/yellow pairs as shown in the above pic. As long as the cable run is under 100 feet or so, there will be no issues.

Dave... that's not a NID that I’ve touched. I found the image on the web, it just shows an outdoor NID with a Smart-Jack built into the enclosure. Around here, outdoor NID’s with Smart-Jacks built into them have a thick door unit where the actual circuitry is housed. I just wanted to make sure that’s what the OP was talking about and not just a standard NID.

Thanks to all you guys. I have learned alot since I posted my un-informed question earlier..lol. you guys rock. I will verify in the morning that it does indeed have the smart jack built in.

You'll notice that the outdoor NID houses 2 circuits, but has 4 jack/plug/terminal sets.

There are 2 sets for each circuit. The top one is wired RJ-48C, using 1&2 and 4&5. The bottom one is wired RJ-48S, using 1&2 and 7&8.

An inside mount 2-slot NID has a slide switch inside to change the jack wiring.

I gtoofed on the above message! My question is this: What would happen if we used CAT5e to extend a T1 circuit about 250' from the Outside Smartjack? I have a pending installation which calls for just that. They already have one T1 that is being fed by a section of 4/24 CAT3 UTP(with one POTS line and one ISDN BRI line as well)..........and they have constant problems on it, but it was installed like that some time ago.

Since you'll be on the customer side of the interface, your best bet for this run would be to use two separate C5e cables, one containing the transmit pair and the other containing the receive. In a perfect world, I'd suggest two-pair, 22 gauge T1 cable where each pair is individually shielded under a common outer jacket.

Cable capacitance over a distance of 250 feet might be enough to cause problems that you can't explain. Once you get beyond about 150 feet, it becomes a finger-pointing festival.

Thank you very much! Do you have any idea locally where we could find the two pair 22 gauge T1 cable in the Hagerstown MD area, since that is where the install is taking place? Other than that would CAT 6 help with the distance factor any?

Quick addendum to the above post. I have found some online suppliers for the 2/22 T1 cable that we might be able to order a rush shipment from, depending on the end user and clients' wishes, which often translate into dollars more so than anything else(penny wise and pound foolish at times).

So another quick question: can we place several T1 circuit sides under the same sheath if they decide to go the separate CAT5e/CAT6 route, i.e. the transmit sides under one heath and the receives sides under the other sheath?

Thanks!

I'd check with CSC in Clarksburg, MD (301-353-1150) for the cable.

As for your second question: Yes, you can place all of the transmits under one cable sheath and the receives in the other. That is done quite often.

Ed said:
Just wire the distant jack at the router as 568B and connect the white/blue of your cable to the red/green terminals. Connect the white/orange to black/yellow pairs as shown in the above pic. As long as the cable run is under 100 feet or so, there will be no issues.

I'm a T1 newbie, about to wire up from my new NIS (same as above) to a T1 DSU/CSU. Based on the pinout of a 586b plug on the router end, I would have wired in the NIS as:
Yellow (CT1) --> Orange (pin2)
Black (CR1) --> Orange/White (pin1)
Red (CT) --> Blue (pin4)
Green (CR) --> Blue/White (pin5)

The picture and Ed's comment seem to have the pair colors reversed, pin1 as CT1, etc. Where am I going wrong?

What you are doing wrong is that for a T1, tip and ring are in the reverse order for the orange pair compared to a 568B cable. A T1 plug should be wired R-T-0-R-T-0-0 from pin 1 to pin 8, where "0" means not used. A 568B plug is wired T-R-T-R-T-R-T-R.

So if you wire the plug 568B, you can reverse the color scheme of the orange pair at the other end and get the same result.

Well I certainly hope he's figured it out by now.

Butch, while you are somewhat correct in the pin assignments, polarity does not matter on a T1 circuit. The only thing that matters is proper placement of the transmit and receive pairs. As long as pins 1,2,4 and 5 are used, that is all that is required.

"A 568B plug is wired T-R-T-R-T-R-T-R. "

Well, sort of on 568B:

Tip 1 is jack position 5
Ring 1 is jack position 4

Tip 2 is jack position 1
Ring 2 is jack position 2

Tip 3 is jack position 3
Ring 3 is jack position 6

Tip 4 is jack position 7
Ring 4 is jack position 8

Yea, I agree that this issue has likely been resolved by now, but it is important to keep even responses to old threads accurate.

Ed you are right. I tested a T1 demark extension in the field, and pins 1 and 2 were crossed. Pin 1 at the near end was connected to pin 2 at the far end, and pin 2 was connected to pin 1. The T1 still worked. So it is OK to just leave it that way?

It's a 4 wire circuit as long as transmit and receive are correct the tip and ring of the pair doesn't matter.

Quote from Ed's post: