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Hi. I've been reading through many of the forum topics and some other sites. I see conflicting information on what type of cabling to use between the Smart Jack and the CSU/DSU.
Can I use a regular RJ45 male connector with the proper pinout and UTP, or must I use an RJ48 male connector with STP?
Can I simply use 4 wires from an existing 100 pair wire? Would this cause interference frame errors, etc...?
Also, are there any side effects of having a break the cable, connected in a punch down? If I do have a break, must I connect 7 & 8 to a ground? I didn't know if it was necessary to run have a home run from the Smart Jack to the CSU/DSU.
Sorry for all of the questions in one post.
Thank you in advance. Jim
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Moderator-1A2, Cabling
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Moderator-1A2, Cabling
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To the best of my knowledge there is no such thing as an RJ48 male plug. We always preferred to use RJ48x female jacks with a patch cord. This would send a loopback to the distant end when the cable was unplugged. I like the idea of a jack with a patch cord rather then crimping a male head onto a cable - I just think it's a better practice.
I found MUCH better results (i.e. fewer problems) with shielded cable. We either used General Cable's T-1 cable (8 pair, each pair individually shielded and an overall braid) or we ran TWO runs of AT&T Cat 3 with an overall shield (one run for the transmits and one run for the receives).
And for the same reason:
When Telco sends T-1s over copper they generally send each side of the circuit over a different cable. If a different cable wasn't available they would pick different binders in the same cable. Yea, you could use 2 pairs (not 4 wires) from a 100 pair cable, but I would pick different binders - and I would only use this if a shielded home run from the Smart Jack was next to impossible. And yes, this all goes back to shielded cables. You really want to keep the transmit and receive pairs separated. If you don't then you run the risk of errors.
You can have a break in the cable at a punch block - but only if absolutely necessary and again - keep the transmits and receives apart. I don't see a need to ground pins 7&8.
A home run of shielded cable is always best.
Hope this helps.
Sam
"Where are we going and why are we in this hand basket?"
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Hi Jim and welcome to our telecomm corner of the internet. What’s the distance between the T1 NID (aka Smart Jack) and you CSU/DSU? That will make a pretty big difference in what options you could use to do the extension and also be a determining factor on how big of an issue you could have if you’re forced to break the cable path and jumper at a 66-block. (As Sam mentioned, try and avoid that if at all possible.) Originally posted by JBova: Can I use a regular RJ45 male connector with the proper pinout and UTP, or must I use an RJ48 male connector with STP? You could use a straight through Cat-5 LAN cable between the T1 NID and the CSU/DSU, yes... But don’t call it an “RJ-45,†‘cause we’ll point and laugh at you. ![laugh laugh](/forum/images/graemlins/default/laugh.gif) (Okay, not really laugh AT you, but “RJ-45†is not a proper term for an ehternet cable/jack despite how many people misuse the term.) Originally posted by JBova: Can I simply use 4 wires from an existing 100 pair wire? Would this cause interference frame errors, etc...?
Yeah, you could use existing infrastructure cable where available. In of itself you should not have to worry about interference as long as the distance is not too great... BUT, but, but... You need to pay attention to what else is being transmitted over the existing cable. Every now and again ADSL and T1 don’t play nice with each other if the pairs are right up against each other... And as Sam mentioned try to get the Tx and Rx pairs at least in different binders (25-pair counts.) Originally posted by JBova: Also, are there any side effects of having a break the cable, connected in a punch down? There’s a point of signal loss, yeah... The distance of the run will be the biggest factor in figuring out of that will be an issue or no. Originally posted by JBova: If I do have a break, must I connect 7 & 8 to a ground? I didn't know if it was necessary to run have a home run from the Smart Jack to the CSU/DSU. There would be no reason to ground 7 & 8.
----------------------- Bryan LEC Provisioning Engineer Cars -n- Guitars Racin' (retired racer Oct.'07)
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Thank you for the kind welcome and helpful advice.
The run is about 1200 feet. There is a usable 50 pair cable, but it terminates into a 66 block at about 800ft. From there it is CAT5e to the CSU/DSU room. In an another post on this site, I read that the maximum distance for this run would be 655 feet. I have nearly twice that.
Thanks again, Jim
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Joined: May 2007
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Moderator-1A2, Cabling
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Moderator-1A2, Cabling
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655' is the maximum buildout from a mux and probably from a smartjack (it depends on the make/model).
Can you get the carrier to extend the smartjack to the Comm room?
There are T-1 repeaters that will easily push your circuit 1200'.
I would NOT. I Say again, NOT try to run a T-1 400' over Cat 5. 40' maybe, no more. You're only asking for a crappy signal.
Sam
"Where are we going and why are we in this hand basket?"
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Thanks Silversam. I plan on making a new run, which will be about 480 feet, with 22 gauge category 3 ISTP cable. Hopefully this will work without the T-1 repeaters. I'll keep you posted.
The carrier did put the smartjack in the main comm room, but each tenant's CSU/DSU is far from that.
Currently, the T-1's connection to the CSU/DSU is as follows: From smartjack, into 66 block, through the 50 pair 22 gauge phone cable, into another 66 block, into a cat3 cable, into a standard cat5e jack, and finally patched into the CSU/DSU with a cat5e patch cable. All of this travels over 1,000 ft from start to end.
Of course it doesn't work. I was told that it hasn't worked since it was installed 3 months ago. So, I hope to fix it, and I want to do it the *right* way.
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From 1000 feet (uh, yeah of course it did NOT work) down to 480 ft... Did the existing path go ‘round the building a couple times or something? :shrug: There’s also an option of putting a change order in with the provider (of course with a charge) and have the T1 NID (Smart Jack) moved to the customer suite... There is also another way for the T1 NID to be moved but of course I don’t recommend things like moving it yourself, since that’s against the rules –n- all. ![wink wink](/forum/images/graemlins/default/wink.gif)
----------------------- Bryan LEC Provisioning Engineer Cars -n- Guitars Racin' (retired racer Oct.'07)
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CnGRacin,
Yes, it pretty much did. Imagine that the room was due east from the comm room by about 480 feet with the drops. It went N-NE to a mechanical room 500+ feet then back to the customer suite. It looks like the installer just punched the T-1 down onto where the old phone lines were connected for that customer.
The provider's policy at this location is to drop everything into one comm room of this 900,000+ sq. ft. building.
Thanks again guys.
Jim
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If you're going to run new cable, be sure it is appropriate. If it were me, I'd use T1 extenders and existing cable pairs. We've had very good success with Patton's units. Probably lower cost than running new cable. Mike
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I made the new run with DS1 cable, the 22 gauge individually shielded twisted pairs. Everything is working great now. Thanks.
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