Re: OT, proper phone wire question?/Twists & Guage ?
On Wed, 26 Nov 2003 18:30:00 -0500
lee <lnx@alltel.net> wrote:
> On Tuesday 18 November 2003 15:36, Derrick 'dman' Hudson wrote:
> >
> > Why are twists so important and why do the faster technologies need
> > more twists in the cable? As an electric signal varies along a pair
> > of wires, a magnetic field around the wires is created and then
> > collapses. This field will induce a current in another wire that
> > passes through the field. That induced current is "noise", because
> > it intereferes with the electric current (signal) that is
> > intentially being sent over that wire. Twisting the wires reduces
> > the size of the generated magnetic field, and also reduces the
> > cable's ability to pick up a signal from a nearby magnetic field.
> >
> > For voice-grade telephone, no twists are needed most of the time.
> > For better signalling and less noise, get more twists. Using Cat 0
> > or Cat 3 should be fine, but the Cat 3 will cost more money. You
> > *may* have noise problems with Cat 0 which will hurt your ability to
> > connect, maintain a connection, and will limit transfer rates.
> > Basically "more is better" when it comes to twists, but also "more
> > costs more". It's up to you to find the desired
> > return-on-investment for cable quality.
> >
> > HTH,
> > -D
>
> Thank you very much for the discussion on twists, I have a
> question..what about actual wire size..cat 3 and 5 are usually 22 or
> 24 guage..suppose one was to use say 18 guage speaker wire..it's
> twisted(like cat), it's unshielded(like cat)..but a bit larger..less
> resistance is my thinking..where am i wrong here..not enuff twists
> perhaps?
>
> Thank you all very very much for your time..
>
> Lee
>
Good thinking.
In legal building standards for example, the standards specified are
'minimum required without having to go to jail.'
Going up one more guage in wire size does indeed reduce resistance and
associated energy waste in heat given off, and allows the maximum amount
of energy to arrive at the appliance concerned, with the associated
economic factor. There's the greater initial cost which concerns the
short-sighted initially, but cost savings over the longer term which
soon recoup the initial investment, and mean money in the bank
thereafter for those that are capable of thinking beyond the trapezium.
Regards,
David.
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