View Full Version : Networking Question: Splitting Ethernet Cable?

Sir Prospect
14-01-2012, 02:51 PM
Hi everyone,

This may end up being a stupid question, but please bear with me,

I am trying to setup the Thomsom tg585v7 modem in the middle of my house, and I've got 2 sets of devices I need to connect to it,

In the Lounge, I have a Internet TV and a Ubuntu Desktop, and in the study, I have a Amahi Server and my main computer.

I'm not sure how to explain it, but is it possible to run a ethernet cable to each room, and then split the ethernet cable to run to each device using a HUB sort of thing? (Like how it happens with USB Hubs).

In Contrary, to say, running a separate cable to each device?

Image half describing what I mean >> http://i1085.photobucket.com/albums/j423/sirprospect/idea.jpg

Cheers and Thanks in Advance!

14-01-2012, 03:02 PM
Those red circles on your picture, what you want in those locations are called a switch or switching hub.

Do NOT get a plain 'hub' aka repeater (although they are very out of date so probably you wouldn't find one anyway)

Also, check the backplane capacity. It should add up to the number of ports x full duplex throughput per port - if it's significantly less then it's a cheap switch. It will work, but it means you can't run all ports at maximum throughput at the same time, so if all your computers are transferring large files you will get slowdowns.

Alex B
14-01-2012, 06:52 PM

Long as you're only using 10/100 connections these are fine, they don't support 1gig from memory.

You need one on each end of the cable IE it will still take up 2 ports on the router.

The Error Guy
14-01-2012, 08:20 PM
Alex's conecept is a good way to do it, but it will NOT support gigabit which needs all 4 pairs. Cat5 (10/100mbps) will run on 2x pairs. As I read it they are saying take one cable, split into two and use. The problem is you are using 2x connections over one port so you will be halving the speed from 10/100 to 5/50 I guess (not sure if that's accurate) I think you would want to get two of those splitters. One to take 2x ethernet cables from the router into one cable and another to split it out at the end.

A better way would be to make or get someone to make you a cable that does the same thing, its not too hard to do. If I had the crimping tools i'd do it for you.

14-01-2012, 08:28 PM
Yeah those will only work at 100M, they take advantage of 10/100M ethernet connections only needing 4 wires, whereas 1000M uses all 8 wires.
If you are running and terminating the cable yourself why not just run two, cable is cheaper than any devices to split it. Alternatively just wire it up 4 wire onto two RJ45 jacks using blue and orange on one and green and brown on the other (on the blue/ orange pin positions).

The problem with wiring it that way or using the passive splitters Alex posted is you have to have a 10/100M device on at least one end or force your ethernet card to 100M, otherwise the GigE hardware will detect the GigE capabilites of the other end and try to use it despite not having all 8 wires and will therefore fail to work (I've tried it myself).

Agents comments about the backbone are correct, but it depends what you use it for. If all you want is internet access for multiple devices or aren't likely to do a lot of simultaneous copying or streaming between devices then it's not really important.
I have a TP-Link 5 port GigE switch for my home network and it works fine with 3 PCs and a Tivo hooked up to it.
Otherwise just by a cheap 5 or 8 port switch,

Alex B
14-01-2012, 08:32 PM
tg585v7 only supports 100meg, but yeah could be an issue later down the track.

14-01-2012, 08:42 PM
Either run 2 cables to each room or put a switch in each room, that's what I have.

I have a single CAT6 to each room and then in the office I have a switch/printserver combo giving me 4 ports, in my workshop I have an 8 port switch, in the boys room a 4 port switch. Bit overkill but then I picked up the 2 normal switches for a $1 each from the recycle shop