ISDN and split pair

[irzyxel]

im a bit confussled here,
for once, what exactly is "split pair"
... what im trying to do is to replace an isdn cable with a longer one.
so i simply crimped some western plugs on the end and plugged it in, but it didnt work.
measuring the old and new cables, i found my own crimped cable and all isdn cables i found in the storage show as "split pair " on all 8 pins, the cable im trying to replace doesnt.
what am i doing wrong here ???

 

[AvayaNovice]

Hmmm.

ISDN usually isn't all that sensitive to the type of patch cord you're using. I used to use just typical 8 pin flat satin cords, wired straight through.

What distance are you running it? Is the cable you made straight through, or a crossover?

 

[TouchToneTommy]

What are you testing them with that is showing "split pair". Some simple testers, that are actually capable of determining splits, need a minumum length to accuratly find splits. If the cable under test is too short, like a patch cable, they will falsely show splits.

Anyway, a split pair is when you use two conductors from different twisted pairs in place of where on twisted pair should be. (clear as mud?)

 

[skip555]

to expond a little on touch tone tommys answer a split pair is like when you find a jack that someone has wired useing solid green and solid orange becouse they were the closest matchs to the red and green called for on the jack .

you now have a split pair one conductor of each pair being used .

 

[Servamatic]

You need to be following the correct pinouts, simply crimping a plug on won't work.

Here is a link to show you pinouts.

http://www.servamatic.net/html/pinouts.html

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[AvayaNovice]

Hmmm.

I would have to say that "simply crimping a plug" as long as it's the same on both ends would indeed work for ISDN for the telco side to the actual CPE. ISDN is not sensitive enough to have a problem with split pairs and what not. You can use flat line cord (obviously no pair twists in that) or any non twisted pair voice grade cable.

I don't think that's the problem here.

As an installer, I have installed many a drop for ISDN connections in Northern California... and our company policies (this was a bell oriented activity) were to use standard flat linecord. So any straight through cable should work for the telco side to the CPE. Now as far as CPE to whatever else, that's a different story.

 

[Servamatic]

That may be true, but building habits and doing things one way develops better job performance.
When you do things the same, you build repetitive habits which prevents mistakes.
Just my opinion, but then to each his own. I just prefer to keep my track record of zero mistakes that the customer sees.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[irzyxel]

ok ummm
its a standard flat cable, no tp, so split pairs shouldnt even be possible.
the cable im trying to produce is like 8 meters, the original thats not showing the split pair is like 3 meters ... im using a btr kapri for testing.

wire order is ok, else the testing tool should complain if i switched some.

 

[daronwilson]

Actually building habits is good, doing things one way is rather narrow minded. Last thing I want to hear when I hire a qualified technician is "but I always did it this way...." for everything I tell him to do. But then again, I can't tout a track record of zero mistakes, nor can I actually believe that.

There is nothing technically incorrect about crimping plugs on wire. There are proper tools, proper plugs, and proper techniques. More importantly, if it is the ISDN side of the circuit, it's telephone type circuitry and flat satin line cord is just fine. If I had to go order custom lengths of 4 conductor flat satin for every installation I'd go nuts. We keep 1000 foot rolls of it and make what we need for telephone circuits.

The original post and follow up is a bit too criptic to be understood. It almost seems like he may be on the LAN side of the ISDN connection, in which case we are referring to normal data patch cables, and that could be his problem. I'm not familiar with the tester used, nor can I really tell what he is trying to tell us.

The ISDN side should run on normal phone wire with no problem, you just need one pair to connect it up and it really isn't very critical. The LAN side of the circuit, from the modem/router to the computer is generally ethernet and that wiring does need to be twisted pair, data cabling, terminated correctly.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[AvayaNovice]

I agree.

And in no way am I saying he should do it in his own order, I agree that it should be crimped according to standards; however, for the sake of diagnostics -- I'm just saying that probably isn't the issue.

Nick

 

[JBeav]

Der Name des KAPRi mit den neuen Leistungsmerkmalen lautet KAPRi plus. Das wichtigste neue Leistungsmerkmal ist die Erkennung von "Split Pair"- Installationsfehlern.

A split is when the tip or ring of one pair goes to the tip or ring of another pair.

You followed the same pinout as a known working cord. You tested for continutiy and wire map. Are the plugs the same? Is it possible the jacks/pinout do not match the ISDN interface...two wire (4&5) or four wire (1,2,4&5)?

Oh well,

Jeff

 

[irzyxel]

4 wire, as the original cable, both simply have the middle 4 pins active,
here its 3/6,4/5 btw

 

[skip555]

have you tried cutting one plug off and reversing it ?

thats what I'de do at this point.

 

[irzyxel]

yeah, long tried also the tester would complain about swapped wires

 

[AvayaNovice]

Here's a few questions:

What type of cable are you using?
What type of ends are you using (RJ45, etc. and are they for stranded or solid wire)

Physically inspecting the ends, do you notice that all of the pins are depressed fairly evenly, and from a side angle can you see that the "teeth" are fully embedded into the wire?

Have you got any other testers available? Perhaps you have a limited amount of continuity.

What county are you in? Are you positive this is ISDN and not some other type of circuit?

Have you tried using a standard telephone line cord, will it work with that?

 

[Servamatic]

Daron

Read my quote, I said zero mistakes that the customer sees.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[daronwilson]

Richard,

I read your quote, still don't belive it.

The only real way I know of to make no mistakes is to do nothing. Either your customers pay no attention to you while you work, or you are truely perfect.

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[AvayaNovice]

Everyone makes mistakes in this industry, there are far too many aspects to nail everything down, cross your T's and dot your I's. It's my opinion that the best craftspeople in this industry are the ones that realize their mistakes, take them in stride, and do what needs to be done to fix those mistakes. If you don't mistakes, as all good sayings go, you'll never truly learn anything.

I try to make as few mistakes as possible... but when you cover so many different little things, it would be impossible not to overlook something, somehow.

 

[Servamatic]

I give up....obviously you don't understand what I said.
When you make a mistake do you advertise it to the customer? Or do you fix it without making an issue of it?
If you advertise the fact you made a mistake, so that your customer knows it...hey..whatever.
I myself like to double check myself and keep the improper information from my customer. Give them the good news, I don't bother them with my screw ups. i.e. I don't let the customer see the mistakes.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[AvayaNovice]

I think that's pretty inherent with the business.

I think even then so, sometimes mistakes do happen beyond your capability of discovering them.

But I see your point.