atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring "Split" CAT5 wire - 2 pair data / 1 pair telco?

Thanks Derrick, this is a great forum that I am glad to have found. There is so much knowledge and resources available here.

GO GATORS!!

Its is easy to do with Bix using pig tails. You can run 10Base-T and phone over Cat3 wire if you had too. If you got a house built back in the 80's and you can't re-cable it ! But you have 3 pair you can still have a hard wired home network.
Cheers:
I am Canadian and love bix :toast:

Working in healthcare has given me a new appreciation for following standards. And that's saying a lot, because I've always been a stickler for following the standards.

We had a facility cabled recently where the installers didn't follow the industry standards and didn't follow our specifications. They used electrical staples to secure cables in the attic, had too much jacket stripped off at the terminations, too much wire untwisted, etc. Some of these runs actually certified, but there were lots of dropped packets and the computer would frequently drop off the network altogether. Sure, you had a link light at either end, but there's a hell of a lot more to it than that. The installers were sent back out to re-terminate, remove zap straps and staples, and certify. While you cannot undo physical damage to a cable, the difference was noticeable. Not a big difference in the test results, but from a practical standpoint, the computer stays connected to the network and the transmission errors have dropped way down.

At one of the hospitals there was a cable that we suspect was damaged during some unrelated construction work. The cable had a marginal pass with the certification meter, with return loss being the worst offender. That's a good sign the cable was probably crushed or kinked somewhere in the ceiling. The reflections were causing collision errors which a normal workstation was able to deal with reasonable well. Unfortunately this drop was used for a diagnostic imaging workstation, and the software was very sensitive to latency and transmission errors. Almost every time the software tried to communicate with its server it would time-out.

My point here is that just because something appears to work when you do something like splitting a 4 pair cable for voice and data, or running data over a 3pr Cat3, it doesn't mean it's working very well and it certainly won't work in all situations. It's like using the "boot" many cars have as spare tires. Sure you can get from point A to B, and you can probably get away with driving faster than the rated speed. Nobody here would want to drive on that boot any longer than absolutely necessary. You wouldn't let a tire shop to put 4 of those on your car and tell you it's good enough.

If you're doing something as a professional, you do it in a profession manner. I split a cable for two computers in my house, so yes, I'm very much aware that it is possible. I would NEVER do this for a customer, and I would never let a contractor get away with doing this in one of my facilities. It either gets done properly, or it doesn't get done at all. Even a house built in the 80's can be cabled properly. It just takes the right expertise, tools, time, and materials. If someone isn't willing to pay for the work or the don't want to see any raceway, then perhaps they should stick with wireless.

If splitting pairs should never be done, then technically should POE run on a seperate cable all by itself as well? POE uses a "spare pair" Just something to think about.

Also I don't think it is quite fair to compare using spare cat5 pairs for a second device to putting staples through a wire. The first does not meet a volunteer standard, the second is just plain careless.

Never is a strong word. I have been in business for twenty years plus now and I used to say never a lot. I don't anymore. For example: one of my oldest and largest accounts wanted a printer connection in a cubicle in the middle of the room where the cables are fed from an underground conduit. It is stuffed full of cat5 and cat3 cables. There is no way I can get a new cable in the conduit without pulling it with a lot more than 25 pounds of pressure even taped to a snake. I will damage the cable and possibly damage the ones already in the pipe. I explained this to the customer. They understoodd but they wanted the printer and wireless is not an option. I told them that it wasn't standard practice but that I could use an adapter to split the pairs at both ends without modifying the cable itself and thus provide them with an additonal 100baseT connection. This was not a code violation, just a violation of a volunteer standard. They said go ahead. Five years later the printer cat5 connection still works, as do all the other connections in the cubicle, with absolutely no problems.

Sometimes I think we installers protest too much and we sometimes loose site of the big picture...make the customer happy!

Make the customer happy BUT do things the right way whenever possible, and explain to them it may not work right if you have to deviate from the established way of doing it.

Jeff that is exactly what I have been trying to say since this thread began. westflgator provided the OP the answer to his question. Me...I just ramble on!

I love it when a plan comes together!

Everything I have ever seen or heard:

10 or 100 = Cat 5 cable - uses 2 pair

1000 = Cat E or above using 4 pair.

Lets be honest here guy's....You just plain shouldn't do it...Unless your at home working on a project for yourself...almost out of beer and the game is about to start...Other than that get busy and run another Cat 5...Problem solved. :toast:

Come on now. I respect everyone here and I think this has been a really good discussion. And with that in mind I have to say that to say never run two devices on one cat5 e is like saying that a telco should never put two pris on the same copper pair cable. Sometimes you just have to do what you have to do, when another run isn't possible.

Also, its okay to run up to 44 volts DC of POE over one or two pairs of a cat 5e with no problem but a second ethernet connection or a 24 volt or 48 volt analog connection instead of POE is a problem? POE is designed to use in place of USB because it is cheaper than using USB repeaters. I am not convinced that a tdm phone or second ethernet (up to 100mbps) can be more detrimental to the cat5 run than 44 volts dc.

I also know that some tech companies such as Simplex Grinnell (a Tyco company) are requiring their techs to install two voice and two data jacks to each workstation using 2 cat5e cables not four. They seperate the pairs at the patch panel end and at the workstation end. This has become standard practice in their offices and so far it seems to work fine.