Split a network cable

[alonebfg]

Ok While reading an artical in my usuall magazine micromart there was a peice in there about splitting an RJ45 cable into two. I have a hub at home but have just got a new pc and where it is wirless is not good at all. i have already got one cable in but it took me 3 days to do and dont want to do it again. So reading this artical gave me the idea has anyone done this and if so does it work and how fast.

basicy it works like this

port 1

orange/white to pin 1

orange to pin 2

green/white to pin 3

green to pin 6

port 2

blue to pin 1 normaly orange/white

blue/white to pin 2 normaly orange

brown/white to pin 3 normaly green/white

brown to pin 6 normail green

basicly you make two points from one cable hub at one end just save running another cable befor i comit myself and upset the other half if this works there will be less mess she wont have to help and it would take 30mins instead of 6 hours. my question does it work and if so at what speed.

[webman]

Yes I do this at home and works fine. It's a rented house, so all cables are surface mounted and clipped to walls/skirting etc. so I really had to keep these to a ninimum. There's a few picutres on my gallery.

 

Connection speeds are 100MB (on 100MB cards and switches, gigabit is not possible as it uses all pairs) but file transfer speeds vary depending on protocol (I use both NFS and SMB/CIFS) but is usually between 6 and 11MB/sec

[Midget]

what's wrong with just using a small switch? They're only £10

[alonebfg]

its not the switch its the cabling and save space looks better i think. thanks webman.

[john]

It does work, I have done it in a few places as a last resort type of setup as its far better to do it the correct way, CAT5e is cheap as chips as are network switches, just get an extra switch and stick it at the end you need it.

[alonebfg]

thats ok but sort of plug scokets problem in that area pc monitor xbox wii tv skybox all there and no more plugs not without being silly. Its a kids games room so i have tried it today i dont need silly speeds and it works really well (if i put switch there complaints about more eletric being used ) and kids wont switch it off or play with it. At the moment they have to unplug the rj45 lead and they have broke that twice in two weeks so breaking a switch will be really easy.

[badboyvtec]

i do it all the time even here at work. works fine.

[Andi]

We have lots of problems with split cabling at work. Most of the network was cabled with Cat5 and split, and it does often cause problems for us. Less reliable, speed issues, other random issues that magically get fixed if the point is rewired to use all 8 wires.

 

However, I imagine that it would be fine to do as a one off, especially at home where it's not going to take quite the battering as work networks do.

[badboyvtec]

Generally I have only done it in places where A: Running a more than a single cable would be aggrevation, or B: For a printers in an office was an afterthought. (Only 10meg for a printer anyway.)

[Butuz]

Splitting like this can cause problems with managed switches because they sense the two communications channels via the one cable as lots of collisions etc.

 

If it's for the home then you will be fine - but I would not do it in School.

 

Andrew

[Geoff]

Splitting like this can cause problems with managed switches because they sense the two communications channels via the one cable as lots of collisions etc.

 

By that logic, what happens when you plug an unmanaged switch into a managed one?

[Andrew_C]

Splitting like this can cause problems with managed switches because they sense the two communications channels via the one cable as lots of collisions etc.

DOH! You need to split the cable at the hub/switch and connect to two ports!

[plexer]

Yeah you are going to have problems if you only split it at one end.

 

You split it at both and then each connection is plugged into its own switch port.

 

Ben

[redsnappa]

The unused 4 cables in a Cat5 cable are there for a reason, to decrease crosstalk, an increase in crosstalk would cause a reduction of the signal quality on any cable that was split as in the Micromart article.

 

If the signal quality falls below a certain level the network speed would reduce to 10 Mbps through the auto negotiation process.

[Geoff]

Also, although most people will hopefully know this, don't try and use these splitters on 1Gb links or PoE enabled switches!

[petectid]

The unused 4 cables in a Cat5 cable are there for a reason, to decrease crosstalk, an increase in crosstalk would cause a reduction of the signal quality on any cable that was split as in the Micromart article.

 

If the signal quality falls below a certain level the network speed would reduce to 10 Mbps through the auto negotiation process.

 

How do these cables reduce crosstalk?

[Geoff]

How do these cables reduce crosstalk?

 

Twisting wires decreases interference because the loop area between the wires (which determines the magnetic coupling into the signal) is reduced. In balanced pair operation (as in Cat5/6), the two wires typically carry equal and opposite signals (differential mode) which are combined by subtraction at the destination. Thus the noise from the two wires cancel each other in this subtraction because the two wires have been exposed to similar EMI.

[greenfieldsupport]

Sounds silly to me, surely there'll be a problem with cross talk as there are more active wires????/

 

just run two cables you cheap people , even we can afford them!!!

[petectid]

How do these cables reduce crosstalk?

 

Twisting wires decreases interference because the loop area between the wires (which determines the magnetic coupling into the signal) is reduced. In balanced pair operation (as in Cat5/6), the two wires typically carry equal and opposite signals (differential mode) which are combined by subtraction at the destination. Thus the noise from the two wires cancel each other in this subtraction because the two wires have been exposed to similar EMI.

 

"Wikipedia" Geoff

[badboyvtec]

why shouldnt you split a cable with a gigabyte link? (WORKSTATION?)

[alonebfg]

ok sorry to cause such a debate. This is for home use would not dream of doing it at work. Also it stopped me getting a ear bashing from the misses RE mess time and wasting time that i could have been painting the fence. I was told that it could be dome on cat 5e and 6 only as the 4 spare wires are redundent unless using POE or 1gb lan in wich case i would not work. As for interferance if it is done right it should work fine. And it does took me 5 mins to do now kids have xbox and pc on network working fine and wii runs off pc via conection sharing. thanks for the help and the mrs is happy as well as i got the fence painted did not spend all day messing with poxy computers as she puts it.

[greenfieldsupport]

why shouldnt you split a cable with a gigabyte link? (WORKSTATION?)

 

My guess is with the increased rate there will be more crosstalk, which will further compound the problem of using all 8 wires in the cable..

 

Same reason why you need an 80pin (40 real 40 shields) cable for fast IDE Drives rather than a 40pin....

 

[meastaugh1]

why shouldnt you split a cable with a gigabyte link? (WORKSTATION?)

 

Because all 8 cables are used for gigabit, whereas only 4 are used for 10/100, therefore theoretically leaving 4 redunant cables.

[alonebfg]

not really if you consider the cat5e/6 is disigned for 1gb and the max you and send down 4 is 100mb X2 which is not as much data as it is designed for (sory about the spellings hope the fourm gets a spell cheack soon lol)

[matt40k]

not really if you consider the cat5e/6 is disigned for 1gb and the max you and send down 4 is 100mb X2 which is not as much data as it is designed for (sory about the spellings hope the fourm gets a spell cheack soon lol)

 

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