On Sun, Sep 26, 2004 at 04:25:41PM +0100, Ted Harding wrote:
Hi Folks,
I had always laboured under the belief that when you implement a network using coaxial ethernet cable, you basically had to have a single linear cable with pick-off at T-pieces along its length, and that branching coax structures were not on.
In particular, if you needed, say, to connect a laptop [C] to an ethernet between machines [A] and [B], and it wasn't feasible to extend the cable beyond [A] or [B] to reach [C] but the middle of the cable itself passed not too far from [C], then I thought that the only solution was to bring the cable in a long loop to [C] and connect to a T-piece in the middle of the cable. I.e.
[A]--------- -------------[B] | | | | | | | | | | \ / T | [C]
However, thinking about it a bit and then trying it out, I discover that you can in fact set up a branching coax network. The trick is to use spare T-pieces to implement the branching. Like this:
[A]----------T-------------[B] =I [T-piece at 90 degrees] | | [C]-----=I [T-piece on branch cable] | | [more machines on branch if you like] | =I [terminated T-piece to close branch]
The trick is the first T-piece at 90 degrees, whose lateral ("male") insert is plugged into the "female" socket of the T-piece doing its usual job on the main cable. The ("female") end of the "branch" cable is then put onto the other "male" insert of the first T-piece at 90 degrees. This piece of trickery ensures valid connection (and indeed functions just like the normal connection at the ethernet card).
You don't have to use a T-piece at 90 degrees, you can get a convertor... I have a bunch of them in a bag here, and a serious amount of coax cable.
More than happy to donate them to anyone that wants them, they were being thrown out a while ago from an office above where I work :)
Cheers,