T1 Wiring

Posted on 2008-10-13
Last Modified: 2013-11-09
Hi there, I'm trying to extend T1 circuits and I need to know if Im doing it right.  I'm taking it from the NIU that the phone company installs and taking it inside a building to an RJ45 Jack (568b)  I know that they run on 1,2,4, and 5 but do they swap blue/white and white/blue like a normal data connection would?  And could someone clear up the order of a 4 wire cable for me?  The Green Red Yellow and Black  What's the order in relation to the orange and blue pairs on a cat 5 cable?  Thanks
Question by:novaman64

Expert Comment

ID: 22706158
If all you're doing is extending it, and it's less than 1000feet you can just make a really long (normal) straight cable with the single swapped wire.

Author Comment

ID: 22706199
Its an 1100 ft run...

Accepted Solution

razorwoods earned 250 total points
ID: 22706393
You're still fine.  I like the 1k ft rule, but in actuality you can get away with up to 3k ft off set from the smartjack, however you should really start thinking about a repeater if you go to 3k + ft.

Most repeated T1 spans are two metallic wire twisted pairs with regeneration around 36dB insertion loss pts based on 772KHz NYQUIST (one half the T1 line rate), and Roughly at 6000 Feet, or depending on AWG used.

CAT 6 twisted pair can be used, as long as transmit & receive are run in separate cables to reduce the incident of cross-talk errors when T1 signal losses are 15dB or greater between TX & RX.

At 1100ft you're fine without a repeater and within the same cable.

Author Comment

ID: 22706530
So with that being the case then what color (T1) goes to what pin number (RJ45 - 568B) jack?

Expert Comment

ID: 22706581
Pins 1 - 8 going Left to Right (568B ATT)
O/ O G/ B B/ G Br/ Br

** Again standard straight cable.

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Expert Comment

ID: 22706809
EIA/TIA 568B                            
                   Assignment   Pair    Color - UTP     Color - Old Style
   +--------------- Tip Pair 2  2       White/Orange    Black          
   | +------------- Ring Pair 2 2       Orange/White    Yellow
   | | +----------- Tip Pair 3  3       White/Green     White          
   | | | +--------- Ring Pair 1 1       Blue/White      Red
   | | | | +------- Tip Pair 1  1       White/Blue      Green
   | | | | | +----- Ring Pair 3 3       Green/White     Blue
   | | | | | | +--- Tip Pair 4  4       White/Brown     Brown
   | | | | | | | +- Ring Pair 4 4       Brown/White     Orange

Author Comment

ID: 22707078
So since the T1 one only uses 4 wires at the pole, assuming I maintain the same color codes for the 1100 ft run between the pole and the jack (black, yellow, green and red)...  The black goes to the white/orange, yellow goes to orange/white, green to white/blue and red to blue/white on the jack?  

Then from the jack I just use a standard cat 5 cable to the router which is only a 4 foot distance?
LVL 50

Expert Comment

by:Don Johnston
ID: 22707122
If all you're doing is extending the cable, you don't move any pins/conductors. Just straight through.

Expert Comment

ID: 22707648
In other words, if you're just extending the line it you just take same pin to same pin.  Aside from ' standards ' it wouldn't technically matter what colors you used or if you crossed any pairs.


Author Closing Comment

ID: 31505669
partially correct, the ISP helped resolve

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