atcomsystems.ca/forum Forums General General Telephone & Systems Information 25 pair... Category Question

We still stock thousands of feet of ivory and gray quad wire ("JK") for minor residential work. We would never use it for new wiring installations, but it sure comes in handy for surface runs along baseboards, temporary drops and stuff like that.

FCC ruling or not, it absolutely makes no sense to tap off of an existing run of JK wire with twisted pair. The chain is only as strong as it's weakest link. Doing so would be about the same thing as tapping a 1/2" water pipe with a 1" run!

I think the ruling wouldn't apply to extending existing embedded wiring systems. I think their intentions were to just prohibit any NEW installations using quad wire which is understandable.

I read several articles in the link provided, looks like they are just trying to sell more copper. They even elude to CAT 5 being needed for DSL. To follow what these folks are saying you could no longer use non rated 25pr that's been in buildings for years either, at least using their logic. Like you Ed I don't use it on new installs or pre-wires. Can't tell you the number of phone systems I've worked on where whoever installed them used existing quad and I don't see those presenting a problem.

Quad is a bad idea, if the customer ends up adding a second line down the road, there will be cross-talk. In my area, the LEC wants quad running to the outside due to the reason that Bill mentions. We use outdoor twisted pair instead, but the EC's are bad for using quad everywhere wired in a ring fashion.

I just got done pulling in a 12pr to replace 4 quads cause they were adding a 9th line, these were long pulls and no complaints of X-talk. The only real problem I've seen with quad is the non-terminated pair acts as an antenna and picks up radio interference in areas prone to it.

Twisted:

Nobody will disagree with you that it's best to use twisted pair wiring. That's a no-brainer in this day and age.

It's when you go into a home that was built in the 1970's (I lived in one that was brand-new at the time) that was prewired by Southern Bell with a quad loop. Of course, many homes much older were wired with lesser-quality wiring throughout the country. I am just using this house as an example of my personal experience, even though I was a very young kid at the time.

So here it is over 30 years later and I am called to add a jack in a bedroom in a similar house built in the same era and wired in a similar manner by another Bell company using the same standards. There is a piece of that same quad wire running across the attic (pretty much a Bell standard for those "just in case" add-ons).

From the 1950's through most of the 1970's, six volts AC (actually 6.8 volts AC) was frequently run across the second "pair" in quad to provide power for lighted dials in Trimline and Princess phones. This came from a local transformer. Now I must ask; if a dial tone pair can operate in harmony with 60 Hz AC power within the same non-twisted pair environment for at least two decades, why, all of a sudden is it such a sin to use this same pair for anything else? I mean, let's face it, this was 60 Hz AC that was INTENTIONALLY placed on the second pair and we managed to live through it.

So, back to the matter at hand. Do I run a piece of identical quad wire to the new jack and keep the wiring system intact? Of course I do. What's the point in running CAT5 or even CAT1 for that matter, to the new jack? It's what I am tapping from that determines the transmission quality for the entire wiring system.

This goes along with the "CAT5" requirement for DSL circuits. It's CAT NOTHING before it reaches the premises for thousands and thousands of feet. DSL is designed to continue working that way well-inside the premises. Flat line cords, DSL filters, you name it.

Running CAT5 from the NID is not going to do anything to improve the thousands of feet of CAT NOTHING cable bringing the circuit to the permises. Take a look inside the typical residential copper network interface (or commercial for that matter). There is nothing that is CAT5 in them, it's all traditional CAT NOTHING; protector modules, jacks, etc. Unless the NID is electronic, as in deriving circuits from existing pairs, you can run speaker wire to the phone jack with minimal risk of failure.

OK........I will buy the fact that if it's a new home run from the NID to the jack, maybe it's a good idea to run twisted-pair cable. Maybe in the future, when all of the millions of 80+ year-old homes in the US are gone (along with their old quad wiring), then twisted pair will become the norm.

Of course, my whole response here a bit extreme, but this is the point I am trying to prove. Any TELCO service delivered to the premises MUST be capable of operating over existing wiring. Some of it has been in-place for many, many years.

If people have to have their homes rewired to utilize a new telco service, they might be resistant to subscribe to it. That's what the telcos are banking upon, hence the reason that anything they have to offer must operate over the existing copper network, like ISDN and DSL.

Now, when you get into fiber to the home, an entirely new technology, people understand that they will need new wiring and expect to pay for it. That's an entirely different, and understandable subject.

In taking a final dig here, we had two lines working for fifteen years with no problems on our quad loop. My sister had a private line and talked on it all the time. It's all about how it's handled and installed.

Well here's a situation I had Ed;

Back about 10 years ago (not knowing any better) I roughed in a commercial unit with quad. The business that was in there had two lines running through the quad and you could always sort of faintly hear the conversation that was taking place on the second line. I noticed this right away and blamed it on the Rat Shack 2 line phones that the customer provided.

Two years ago, a new business ended up in that unit and Bell did the new install for them. I was on site doing the security system for the new owner the same day the Bell techs were there. They started replacing the quad with Cat 3 and when I asked why they were doing it, the tech told me the customer was running 2 line phones and the cross talk was bad. They were now using the NT M9316 phones so I know the phone quality was good. After the quad was replaced, no more x-talk. I vowed to only use the quad in my van for security systems only from that point on!

Twisted:

I was only referring to residential applications in my prior rampage. I know that it's a whole lot different in a commercial environment, especially in a "star" configuration. That's a whole lot more wire than a traditional residential loop that hits four or five outlets.

Yes, the Bell companies, if they will even install inside wiring anymore, install only twisted-pair on new installations. So would I. I spoke of extending existing residential wiring, that's all. There is a major difference here; maybe I should have been more specific. Sorry about that one!

I still have a hard time understanding how two phone numbers can travel through thousands of feet, often miles of "CAT NOTHING" outside plant cable, with hundreds of other circuits under the same jacket. Yet all of a sudden when it comes inside the building, the hundred or so feet of unpaired cable causes these circuits to interfere with each other!

I still say cheapo one-, two- or four-line phones cause inbalance on the pairs resulting in amplification of any potential for crosstalk. Switch hooks that only open one side of the line is a classic example. The more phones sharing the same lines, the more line inbalance is created. This makes crosstalk much more noticable.

Help me here Ken and Bill!

You are right, Ed. Either that or there was some damage (like a staple) somewhere in the quad. Some real tight kinks can also cause "bleed".

One time I did have x-talk in new quad, I'd had a bad buried cable and laid almost a mile of quad in the ditch. Two 4 party lines. Yes, it would x-talk (only when both lines were in use :dance: ) But it kept them in service for a few days until we could get the bad spot located and another piece of cable buried and cut over.

KLD

Good point Ed!

KLD had a valid one too, could very well have been a staple, I have misfired before!! :dance:

I have had the two line phones create X-talk, I don't remember the brand. I also have seen some phone systems create X-talk. If I have a report of X-talk the first thing I do is check from the NID in to see if I can see anything physical, if not I dial a quite term on one and milli on the other, 9 times out of 10 the X-talk is in the plant. I also have seen some cheap wire (you could actually see the copper through the insulation) that had X-talk. I don't think you can make a blanket statement that quad will cause X-talk...IMHO