2 pair cat5 1

[jeepguy267]

I was recently asked to network about 10 PC's for a customer who's site is already wired. I opened one of the jacks (for a completely separate issue) and found that the 2 data jacks at each location are actually 1 cat5 cable run split onto 2 jacks. Customer swears they had a network working in the space (since then, change in ownership and all pc's and switches are gone). I have always, always, always used 1 run, 1 jack, all 4 pairs, 568A/B. Is it possible to reuse the existing set up and this is something I just never considered or will I need to reterminate all the jacks and the patch panel?

thanks in advance for the help!

 

[dnc16]

Yes it will work as long as they don't want Gigabit and the correct pins are terminated in the jacks. However this is generally frowned upon as a netwrok setup.

 

[Sphoneman]

The cabling obviously was for their voice.We weren't using CAT5 in token ring days. They probably had a wireless network.

The cabling in the condition you found it is not CAT5 compliant.

Are you using the other pairs for voice? If so you run the probable risk of problems from ring voltages.

If you would like to not be getting callbacks & having problems reterminate on CAT5 jacks with a CAT5 patch panel.

Once you hooked up to it, you are deeming good & married to it for life.



Steve
tele-dataservices.com

 

[ttech]

It could have been for DATA or voice, (avaya definity 4 wire digital sets use the same pins as ethernet) I don't see why it would Not have been used for data, Though it is NOT standard, some people are untrained, don't know any better, Cheap etc.....

I have seen people in than past split a cat5 cable onto 2 data jacks 2 pairs each. It would work fine for 10baseT, But woud be not very sutible for 100baseT.

Back when 10baseT first came out Our Customer had ethernet sharing 25 pair cables with system 85 phones cross connected with 2 pair cross connect. The Hubs had 25 pair amphenols punched down on 66 blocks. We would test it with an OLD 286 portable computer with a built in 5 inch green monochrome screen that weighed about 40 pounds. We would boot up the computer we would run this netware script and if we got a log in prompt "it Passed"

Boy how times have changed.


~Don~

 

[Sphoneman]

Don,

Yes we had to very creative years ago, & they didn't have to worry about the speeds. I think that's why they finally havethe newer standards now.

The youger ones today think that they're supertechs if they can install a cat5.I'd love to see them around 1A2 with diode matrix.

Steve
tele-dataservices.com

 

[wires]

All common implementations of 10BaseT and 100BaseT use two pairs. While not ideal the wiring apparently worked before and will most likely still work. I have seen 100BaseT running on two pairs without problems.

If you want to be standards compliant then re-terminate the jacks and patch panel using all 4 pairs. If you need more than one network connection at some of the wall plates use a small hub or switch.

It is not something that I would get all worked up over. There are three options. Try it as is and see if it works, re-terminate the existing wiring or run new. I would discuss these options with the customer and help them make a decision.

 

[ravnz5]

Your 10baseT network only uses pins 1,2,3,&6 so as wires said, it should work. However; If you are responsible for the new client, and your name is on the end result, re-wire and re- terminate to code.

We all need a little help once in awhile. Tony the Phoneman..

 

[skip555]

it will work much slower I did it here at the house to run a second connection into the bedroom internet was fine printing took forever.

best would be to terminate correctly and run new cable where needed or teminate correctly and add a 5 port switch for second connection .

I remeber one distributor who used to push the fact that you could do two cat 5 connections on one cable back when cat 5 was just getting established

 

[Jtodd]

I'll reiterate the fact that yes, this will work (two pairs per port) though not supported by the standards, or not the best idea administration wise. And both 10MB and 100MB work just fine over it, and if you're talking just a few users none would probably notice. But as the number of users goes up, it really starts to be seen in the switch.
Here on our campus, we had a great number of these (actually on cable was terminated on one jack, and we had splitters plugged into jacks and patch panels). In starting to remove them, no one ever really noticed any performance changes when we took out 1 or 2. When we pulled 30 splits out of one 192 port switch, not only did every user on the switch notice, but the network admins saw the performance stats on the switch improve as well.
I would suggest avoiding using split cables at all costs, but with the original posts 10 users, what you've got will work. Though I would suggest that you also avaoid the electrical engineer that tried designing a telecom system for one of our buildings last year. He tried putting 28 jacks on 7 cables, and since there were only 7 cables, 3/4" conduit to feed the 28 locations would be fine.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay