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

So much hair-splitting over copper wire. Give me a coat hanger and I'll give you an Ethernet connection.

Dave Taylor has the specs straight and Ed has reality straight.

how many cat5e coat hangers in 100 meters and how do you crimp the rj45 plugs on the ends ? :rolleyes:

I've come across this at a new customers site,and when we upgraded their switches to gigabit (full duplex)we had to upgrade the cabling.it was a "sparkie" install.it was good for us, not so good for the customer.we always stay with the specs for this reason!

I think we have allowed cable manufacturers to convince us that computer data and phone data can't survive together inside the same cable jacket. We have forgotten that 10baseT was designed to work with exisiting telephone wire using spare pairs. On page 79 of my MSCE Networking Essentials Study Guide is a diagram of how to connect data to an existing telecom wiring scheme...this connection includes the use of 66 blocks and a patch panel.

There is a reason why you can buy cat5 e and cat 6 110 blocks.

Many years ago I did a very large wiring job for a mega church. They did not budget enough for the wiring so I installed cat5 and split it for voice and data. The phone system was 2 pair at the time. I contacted Allied Telesyn about using thier hubs (this was before switches) and what they thought of me splitting the pairs. They said that was what 10baseT was designed to do.

I punched down all the cables on cat 5 blocks and used cat 5 jumpers to patch panels. It worked just fine.

Now a days I don't split pairs unless I absolutly need to but when I do, I usually use an adapter made for this purpose. I have never had a problem whether its two computer connections or one tdm phone and a pc.

Of course splitting does not work with typical gigaspeed which does require all four pairs.

its a TIA/EIA standard I don't believe 10baseT was designed to run on "spare pairs as I recall it was separable cat3 also with the same argument about the "spare pairs "

most customers around here went from coax to cat5 wasn't a lot of 10baseT

i was involved in some early discussions on the TIA cat5 standard and I don't recall dual use even being on the table

10baseT was introduced back in 1990 to take advantage of existing twisted pair (thus the T) telephone wiring. My MCSE study guide says it was introduced to take adavantage of "extra installed pairs". Now does this mean extra installed pairs confined to one jacket? I don't think so. Previous to 1990 my customers didn't ask for an extra cat 3 run to be installed in an outlet in case some new data wiring scheme might be invented one day. Back then I was pulling coax or using baluns with existing spare pairs. Later I converted those "unused pairs" to 10 baseT. Siemon came out with a slew of modular y adapters for just this purpose. They still offer them. You can split for one voice/one data or one voice/token ring or two 10baseT. They officially only meet cat 3 standards but work just fine on cat5 and cat5e up to 100mbps. I know cause I use them a lot when circumstances dictate it and I have the equipment to test and verify the speed.

Twisted pair was invented to prevent crosstalk between the seperate wires. Logically you would have to conclude that splitting cat 5 would be less troublesome than splitting cat 3 considering that it has more twists per inch.

My point is this. Using what you have including splitting pairs has been done for a long time. It works and when it is the only choice you have it is a good thing it works.

there is a lot you can do that "works "

when installing a cabling professionally its best to stick to the standards rather than do what may "work" ..just my opinion

I suggest its not cable manufactures who are driving the standard but rather industry pros

or you can do like Tim and show up with a Gaylord of coat hangers and a pair of lineman's pliers :p

Well I respectfully disagree..The cable companies do push wire at us. They were pushing cat 6 before the standard was even a standard. There was big round cat 6 with a foam core and flat cat 6 and if you were unlucky enough to use that junk you found out real quick that a bundle of flat cat 6 picked up so much RFI as to become worthless. Lucky for me I never used it.

I happen to be a very sucessful cable installer. And the reason is I get the job done and don't force my customers to buy things just to meet a certain standard when the real standard should be...can you get it to work without having problems later. That is the standard I try very hard to adhere to. I suspect that you also do the same thing.

What I was hearing in the origanal question was: Can you use Cat5 spec wiring for both voice and data without compromising the integrity of the voice or data? So in this scenario I am assuming he doesn't need all the conductors for data and he is asking will using the spare pairs for voice cause a problem. The answer is no. It will not affect the speed or interfere with the data if this application requires less than the four pairs. Cat5 has on average 3 twist per inch (although each pair has a slightly different amount of twists per inch). As stated above it is designed to eliminate cross talk even with the higher frequencies. Many times buildings are prewired with Cat5 and that is all you have to work with. If only two pairs are being used for data (10BASE-T or 100BASE-TX)then it will not cause any problems to use the remaining pairs for voice if the wiring is free of faults and the pairs are balanced.

Thank you westflgator (my Daughter would say Go Gators!) for bringing us back on topic and I offer you a big welcome to the forums.