Thin wire or twisted pair?

[Doug Robb]

dsamperi at Citicorp.COM (Dominick Samperi) writes:

>My organization is considering the use of twisted pair point-to-point
>connections as an alternative to thin wire Ethernet. The motivation is
>to reduce our expenses. The environment is one where there is little
>tolerance for network failures (a trading floor). I'm familiar with
>thin wire Ethernet, but know little about twisted pair technology.

>Could somebody comment on their experiences with twisted pair
>connections. Are they cheaper than thin wire? More/less reliable?
>Is there a throughput/bandwidth hit in using twisted pair? How
>large? Is twisted pair easier/harder to maintain?

I have recently been to a few seminars where the suggestion
has been made that the way to go is to blanket wire with
unshielded twisted pair and have a concentrator at some
point. With the appropriate cards in the concentrator you can
run ethernet, apple talk, token ring etc without having
to re-wire the building. Since the seminar's were put on by
companies in the market for the above hardware then naturally I'm a
bit suspicous as to whether this is any cheaper than using
thin wire ethernet in combination with twisted pair as I do
here. For a start the concentrator and cards are big dollars....

On the other hand running twisted pair back to a 10baseT hub
may be quite cost effective if you are not sure about location of
(or want the flexability of moving) serial printers/faxes/terminal 
etc around the building. The rational would be that you have to
run the twisted pair anyway for the above so why not use it for
your ethernet devices as well. In the Psychology dep we run twisted
pair back to terminal servers, have thick and thin wire coax
connecting out mini's, sparcstations and pc's. 
I think this is the cheapest way to go? 
Any comments?

You could consider running thin wire ethernet and twisted pair?
Since thin wire is about $A1.50 a metre you can run one or
two segments (up to 180m) on each floor and dont bother with
the T connectors etc until you need them. 
Then for example you want to connect a sparc station you open 
up the cable tray, fit a faceplate and connector and simply plug in. 
Since you can hang 29 devices off each segment it seems to me that
this is easier than having 29 SEPARATE runs of wire going back to
the 10baseT hub rather than the one in the case of the thin wire.
Also the mac length of the 10baseT run is 100m , 180 for thin wire
and about 500m i think for thick wire.

Just to give you an example. I heard of a firm that got 3 floors
of a new building in Perth wired up recently. Two thin wire segments
on each floor and thick wire segment between floors. No connectors
terminators, delni, desta etc because as yet the don't have a computer
system. The cost for this $A7,000.

They also had 8 pair, PDS (unshielded twisted pair) to 100 outlets
with rj45 connectors back to a distrib board put in at the
same time, cost $A48,000. To actually get a computer network
will need a 10baseT hub etc as you know.
Since they don't have a network yet I don't know that the final
cost of each scenario would be.

doug at psy.uwa.oz.au