[c-nsp] T1 Cables

[Lamar Owen]

On Friday 18 May 2007, Vincent Aniello wrote:
> Are there cables specifically for use with T1s that we should be using
> to connect circuits to our Cisco routers with integrated CSU/DSUs?  We
> currently use CAT5E cables and have chronic problems with errors on a
> few of our circuits.  The cable length between the smart jack and router
> is 25 feet.

The T1's I've had experience with have all been wired RJ48S, which uses pairs 
1-2 and 7-8 of the 8 pin plug (in TIA-568B that would be the orange-white and 
brown-white pairs).  If your cables are TIA-568A or B they have the correct 
pairing.  It's only if you have USOC RJ61 or similar that you have to worry, 
as that splits the pairs.

One poster mentioned clocking; this I would check.  What sort of errors are 
you getting from the controller?  I have one T1 here terminated in a RSM/VIP2 
in a Cat5509 using a PA-MC-8T1.  Some providers have more problems with B8ZS 
versus AMI, and I have seen odd problems with HDSL (PairGain) provisioned 
T1's that were the fault of the carrier's shelf backplane.  Currently, the T1 
that backs up our OC3 is provisioned over fiber with an FMT-6, and that has 
been absolutely rock solid using a standard Cat5 cable about 100 feet long.
-- 
Lamar Owen
Chief Information Officer
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772
(828)862-5554
www.pari.edu