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

Four pair CAT4, (yes, there was a CAT4) CAT5 and CAT5e was being made way before POE came into use. Still POE is only an extra one pair. Gigabit requires CAT6 and all four pair.

You need the 4 pairs so you can steal two of them for the phone and the fax machine.

Well, that actually may be the reason and BICSI and other butt head IT "authorities" wouldn't hear of it. But I kind of like my idea that the whole thing is BS from the cable manufacturers to get more money out of your pockets. Otherwise they would make 2 pair CAT5e.

-Hal

Ha, forgive me for being a PITA, but while I agree 100% with your post, the gigabit issue needs to be clarified.

The gigabit ethernet system that "won" is 1000base-T, which will run on plain old CAT 5e cable, but does require all four pairs.

It is 1000base-TX which requires CAT 6. 1000base-TX uses only two pairs, but it lost the race and is not seen much.

10 gig ethernet requires CAT 6e, making CAT 6 the answer to a question nobody asked.

My point being that I believe CAT 6 is an even bigger ripoff than the two wasted pairs that results from using CAT 5 for 100 mbps and lower ethernet. At least those extra pairs can be used for something...

Jim
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Speaking from a secure undisclosed location.

We have gig throughout our building with all Cat 5e cabling. Works like a charm!

The 1000Base-T standard came out around 1997 I believe, and they would have been working on that for several years prior. It would make sense then for the cabling standards at the time to look forward towards adoption of the new technology which would require 4pr cable, even if the technology of the moment did not need more than 2pr.

Buildings that were properly wired 10 years ago using Cat5e will support Gigabit and POE+ without any need to retrofit the cabling. That's the beauty of following standards. I think we need standards to have the longest life-span possible, and that means building the capacity to use technologies that we don't have on the market today.

A correction to my earlier post: 10 gig ethernet requires CAT 6a, not 6e [no such thing as 6e].

CAT 6a is also called "augmented" CAT 6.

Of course, if people really need to move data at 10 gigabits per second, they should probably be using fiber instead of copper.

Jim
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Speaking from inside "The Rock."

Hal, I remember CAT4 fondly. Bought several dozen spools of it from North Supply. AFTER CAT5 became 'The Standard'. They were 'fire saleing it'. They were selling it for 1/2 of the going price for CAT3. Too bad they didn't have more!

The 1000Base-T standard came out around 1997 I believe, and they would have been working on that for several years prior. It would make sense then for the cabling standards at the time to look forward towards adoption of the new technology which would require 4pr cable, even if the technology of the moment did not need more than 2pr.

Yeah right. Nice try trying to give the IT industry the credit. :rofl:

Where did the 4 pair "standard" come from? Remember, there was 4 pair in the CAT zero days. I think you will find the answer if you look at the Bell System/AT&T 568B standard that was probably written for the old Merlin systems. That was the first use of a 4 pair cable.

-Hal

poe uses the brown pair
telephone uses the blue pair
10Base-T uses the orange and green pair

And their is more than one way to skin a cat5

Bix did it

568B is WECO! There can be no other explanation. The Merlin was introduced in 1983. Executone had a Triad K410 4-pair system at about the same time, but it used the USOC wiring code and as we know, USOC was not adopted for data use.

Good ole' Western Electric...where would we be today without all the suff they provided? 568A was their own private standard. I just loved wiring two pair usoc phones to the white/blue white/grn pair.