Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations strongm on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Installing cat5 with only 3 pairs available 1

Status
Not open for further replies.

LARiot

Programmer
Feb 7, 2007
232
Hi. I have a cat5 cable installed throughout the house but of the available 4 pairs one is being used for the phone. Can I successfully install keystone jacks and connect my computer to a network router at another end with three pairs?

My roommate says I only need one pair but I'm not sure.

BTW, the blue and white/blue wires are being used with the other three available for a network.

Thanks

-Nima
 
It requires 2 pairs. I've never bothered to see what specific wire colors are involved but they are wires 1&2 for one pair and 3&6 for the other, both at the jack, which lead to 2 twisted pairs.

Ed Fair
Give the wrong symptoms, get the wrong solutions.
 
If that is the only option without running additional CAT 5e cable, then the WH-BL pair is the one to use for phone. Depending on how 'standard' you want to keep the wiring, you could wire all the jacks using the 568B standard, and use adapters to select the WH-BL pair on a jack for phone and the others for data on a second jack.

....JIM....
 
10 meg and 100 meg ethernet only use pins 1&2 and 3&6 for data, Power over Ethernet may use other pairs, but it is rare.

1 gig and 10 gig ethernet need all 4 pairs, so you will not get gig speeds.

Here are the 'standard' pin assignments, as you can see blue and blue and white are pins 4&5, the common ones used for telephones.

I tried to remain child-like, all I acheived was childish.
 
Alright, so I'm going to connect pairs 1 & 2 (White/Orange & Orange) and 3 & 6 (White/Green & Green)...

If end up blowing out the entire World Wide Web and the rest of the internet, I'm blaming you guys.

-Nima
 
For 100BaseT, pairs 1 & 2 are used for transmit, and pairs 3 & 6 are used for receive. In installations using POE, pairs 4, 5, 7 & 8 are used for the 48 volt power to the devices.

NCSS NCTS NCTE
 
Crowtalks,

You might want to reread what you post before you post.

The MODULAR PLUG and JACK hardware for Ethernet has 8 pins or contacts NOT pairs.

....JIM....
 
Well put SYQUEST...I've been running and connecting telephone cables for so long, that almost everything that terminates I equate to a pair in my mind. Thanks for catching that.

Jim

NCSS NCTS NCTE
 
Argg and PooPoo to running slow speed phones and high speed data in the same cable jacket. Will it work? Yes. But stand back when one of the 1000 mbps data bit zips by that 5 mbps voice bit! No seriously, you may find the data bits affected by any number of "potential" noise failures.

For home use (short runs), the problems may be minimal and acceptable or livable. Not recommended for commercial install.

By the way, I use 2 cable pair splitters in my home. Roadrunner and digital phones are ok. Wireless works even better.

Much success in any regard.

Regards
Peter Buitenhek
ProfitDeveloper.com
 
OK, I ended up using 6 connections (all but the blue and blue/white, 4 & 5) which was being used for the phone. It didn't work. Ended up buying a wireless USB adaptor.

-Nima
 
Did you ensure the jack at the end was wired correctly according to the pairs you were using at the cross connect? We used to do this from time to time when I was stationed in the desert and we didn't have any pairs left and had to get network connection to a tent.
 
Yup. There is a second cable meaning one connection in between has three cables coming together.

Will this affect it?

Thanks.

-Nima
 
Ethernet HAS to be a home run. If other cables slice into it, it can't be ethernet.

I tried to remain child-like, all I acheived was childish.
 
It sounds like this is going into some sort of demark in the attic or something. So basically all they have is cat 5 phone cables. You could extend those cables (or the pairs that you need) by placing a jack on both cables and a patch cable between the two.

It is not the best way to do it, but it is a way to do it.

"A people that values its privileges above its principles soon loses both."
- Dwight D. Eisenhower (1890-1969), Inaugural Address, January 20, 1953

For the best response to a question, read faq690-6594


 
I tried this over the weekend as well and couldn't get it to work either.

I wanted to hook up my 360 without spending hours in the 150+ degree attic slinging cable, so I took the Cat5e in my office that has phone on blue-white/blue and connected a keystone to the green and brown pairs on 1/2 & 3/6. I did the cross-connect at my 110-block patch bay to tie the colors together correctly for the other jack and no dice. I don't get a bit of traffic to the other end from my switch. It's kind of frustrating, though, because I know that it should work, even if it's not to spec.

Some of my thoughts on the matter:

1) Could changing pairs at the patch bay have caused the problem? I'm going from green to orange and brown to blue, so there is quite a bit of change in the twist rate. Could that be the problem?

2) Did MS use a non-standard hookup on the ethernet of the 360 and actually require more than two pairs for 100 Mbit?

Anyone have any other ideas?
 
Jet, I'm going to step through what I think you want to do so: a)I can wrap my head around it, and b)so others can see it and correct me if I am wrong.

Here's how I would do it:
In your office you have a wall plate with phone jack. That jack is using the blue pair of a cat-5 cable.
Get a cat-5 jack and put the orange and green pairs on it according to the Cat5B spec (Should be color coded right on the jack but if not 1-orange, 2-white/orange, 3-white/green, 6-green. You will have to get another wall plate to accommodate the new jack (or adapt to whatever you are already doing - the important part is to end up with a blue wired phone jack and orange/green wired data jack)

Why Cat5-B? Because that's what I always do - if I never deviate, I don't get as confused. You can use A if you like, there is no difference. Just be sure to remain consistent all the way through.

Now on THE OTHER END of that cat 5 cable is where I assume you have the 110 block. I think that's complicating things unnecessarily. SO I would just put the Orange and green pairs on another cat-5 jack JUST LIKE you did in the office. orange, whiteorange, whitegreen,green on pins 1,2,3 and 6.

Now just get a regular (not a crossover or anything exotic) patch cable to go from office jack to xbox and from equipment room jack to switch and you are done except for whatever config the xbox needs.

I'm not saying that is the only way to do it but I am 99% sure my way will work just fine.

=======================================
"I am owed. I've never got paid. A dude with a pencil is worse than a cat with a machine gun" Bo Diddley R.I.P.
December 30, 1928 - June 02, 2008
 
PS - I should have said to punch the brown pair into its spots on each jack too. They don't carry any information but more wires is more physical strength for the connection and there may be shielding properties that the wires provide.

=======================================
"I am owed. I've never got paid. A dude with a pencil is worse than a cat with a machine gun" Bo Diddley R.I.P.
December 30, 1928 - June 02, 2008
 
I figured out my problem, I think. I was really tired when I was working on this, and I think that I punched down to pins 1/2 and 4/5, not 3/6. I'll fix that when I get home tonight and see if it resolves the problem I'm having.

@LeeMcCauslin - I don't have an option except to go through the 110 block for now. All the line in the house is pre-terminated into it and I'm not about to change that during the summer.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top