Lets get this down once & for all.
What is the proper cable according to BICSI, NECA, CEDIA or any other code setting organization to run from the "Smart jack" or DSU
usally installed by SBC at the D-marc to the CSU/DSU in the data rack or at the MDF?
A lot of installers run Cat 5e or Cat 5E.
I believe SBC uses a plenum rated 2, 4, or 6 pair cable with individually shielded pairs.
What about the use of RJ 48X loop back jacks?
Does anyone have a diagram?
TIA, WaM, aka; Gem

You've got mail my friend.

Gem:

Have a customer who had his Frac T-1 (about 12 lines and the rest for data) run up 3 floors on a 25 pr cable--terminated on a 66M block--then cat 5e to a RJ45 (os some sort) then to the channel bank. Data was run on a Cat5e. I questioned the 25 pr cable -- but the tech who was testing the t-1 said everything was normal--he was real proud of himself---then booked out. Now, how can they get hi-speed from 3 floors of 25 pr cable? Or am I goofy? I would have thought that you had to run a cat5e cable down to the basement.

don't forget much of the lec's cable is cat3 cable. entrance cables feed that T1. the techs install shielded cable to the smart jack for obvious reasons and from there it is now recommended to pull in a cat5 cable or better. You could even get away with a Cat3 cable over a short distance. think about it a T1 is only 1.544 Mb/s. Cat 3 is rated for 10 Mb/s.

I've had several phone company guys tell me that CAT3 is fine for T1, but they recommend splitting the pairs between binder groups. I just finished one install (frac T1 for data) where telco put the smart jack off the demarc with about 10' of regular old cross-connect, then to the demarc extension (about 350') over 200-pair CAT5. We then went from the 66 block at the extension to the rack with about 75'-100' of CAT5e. It even works!

With my experience with T1's (I've done a few, just plant cross connecting) it doesn't even have to be category 3. We've ran T1's on 1800 pair pre-category 3 cable, where it was I want to say either 24 or 26 guage. We always seperated binder groups because the pair twist was less.

I usually see T1's done around here with two pair shielded category 5 cable. T1's aren't anything special, they don't need that... but I think it prevents interference in the customer premise more than anything.

It does not matter what cable is used for T1 when they put it into the building, but if you are extending the smart jack it is recommended to use a special cable that has two pairs, with each pair sheilded. The cable is designed to stop crossover.

could you email that to me as well, please?

could someone explain exactly what an RJ 48x jack does differently than an RJ 45? they look fundamentally the same to me...

thanks!

-tim

They are not interchangable. See site below for a pin out.

https://www.arcelect.com/RJ48C_and_RJ48S_8_position_jack_.htm

mark

Tim, the RJ 48 has shorting bars that create a loop back when there is nothing in it or it is un plugged.

The 48's shorting bars are also used in the case of alarm systems connected ahead of phone systems where the line goes into the alarm system and back out to the phone system. With the shorting bars, you will not lose dial tone if the alarm device is unplugged from the jack.

RJ48x has shorting bars for loop-back when unplugged.

RJ48c has none.

RJ48s is for data, like a 56k

RJ31x is used for alarms to put them in line ahead of the end user and to provide continuity when unplugged.

[This message has been edited by SST (edited April 08, 2004).]