Cat5e 'extra twist on the brown pair' ??

[daronwilson]

Ok this is a new one on me. I have specs for a job that state "When terminating the jack, the brown pair will have an extra twist added before punching down. (Total of 3 rotations before entering the conductor.)" I can take some wild guesses why they might want this, has anyone else seen this request?

Daron Daron J. Wilson
Telecom Manager
LH Morris Electric, Inc.
daron.wilson@lhmorris.com

 

[ChrisAC]

Sounds like a request by someone who knows nothing about data cabling but read something on a web site and so now thinks that he knows it all!

A little knowledge can be very dangerous!!

Ask then why they've made this request.

Chris.
************************
Chris Andrew, CCNA
chrisac@gmx.co.uk
************************

 

[commworker]

From what I have always understood you should never add an extra twist. Just maintaining the twist to within a half inch will be sufficient. I have tested cat6 that would not pass unless the twists were perfect. If this is Cat5e or less I wouldn't pay attention to the guy.

 

[wires]

>(Total of 3 rotations before
> entering the conductor.)

Where exactly is the entrance of the "conductor"?

I guess the (misguided) spec actually means the extra twist should be between the end of the conductor and the cable jacket. I would love to see the guy try to add twists to something inside "the conductor"!

 

[MasterRacker]

If you grab a single strand with pliers and twist, you could probably get some twists in the copper itself....

I'm with everyone else, Someone read some nonsense and is taking it as gospel...
Jeff
Working in IT is like trying to commit suicide with a very small hammer ....

 

[daronwilson]

Thanks folks, just was checking to see if I was missing something. As I read the balance of the specification sheet, they obviously imported the notes from other jobs as they reference how to add wire in the classrooms and this job has none. Who knows where the other ideas came from.

Just when you make it idiot proof, someone comes along with a smarter idiot.

Daron J. Wilson
Telecom Manager
LH Morris Electric, Inc.
daron.wilson@lhmorris.com

 

[4eyes]

As an addition to the evidence against the moron who wrote these specs on terminating the jack, the brown pair is generally not used in either voice or data. The only time I have seen the brown pair used is for a 48v supply to a 8434DX handset on a Definity G3r PBX.

 

[daronwilson]

Well ... When installing stuctured wiring systems, I sell the fact that all four pairs are installed correctly and test so. Is the brown pair used? Depends completely on the hardware and application. If you install AMP ACO style of hardware, various modules can be inserted that use the brown pair for both voice and data. What about gigabit ethernet?

I guess my point is just because your current application doesnt need the brown pair, you should still have the wiring installed so that all four pairs are properly terminated. When I provide a test report with my Agilent Wirescope 350, it reports all pairs and combinations so that the wire is ready for whatever service is needed on it.




Daron J. Wilson
Telecom Manager
LH Morris Electric, Inc.
daron.wilson@lhmorris.com