On (18 Mar 98) Rob Dennis wrote to Holger Granholm...
 RD>  Is this a four-line phone wire or something different?
 RD>  Canadian and European phone systems being different,I wonder if the
 RD> wires used in them are the same or different as well.
 RD>  Our wires are four to make up one line,and some are stranded some are
 RD> not.  This is for the inside wire,not the one on the poles.
Dunno about Canada, but I would suspect that your phones work like ours
do here in the US. It is true that the phone "cable" (grey colored
insulation on the outside) that runs inside homes and businesses has
four wires. The four wires have insulation on them and are red, green,
yellow and (I have forgotten the last one, brown perhaps). It only takes
one pair of the four to connect a single phone line, thus each grey
cable will support *two* individual phone "lines".
Maybe 60 or more years ago three of these conductors were used. I
believe they were the red, green and yellow, with yellow connected to
"ground", and red and green for the actual "line". The unused
conductor was a "spare" in case one of the others were damaged
somehow. Substituting the "spare" for the damaged wire allowed them (the
phone company) to rapidly repair a damaged "line" with out having to
install a new "cable". The "ground" wire was attached to a ground rod
that was driven into the ground outside the house or business.
Nowdays there is only *one* ground rod and all wiring, including AC
power, cable TV etc are connected to this single ground rod. This is to
prevent what is called a "ground loop", meaning having several ground
rods that may be at different potentials, the result of the "ground"
rods having been driven in areas of the property that have a different
conductivity because of differing soil conditions.
I believe our "National Electrical Code" (the Federally mandated
"standard" in the US for all wiring that enters and runs thru a house or
business) now specifies what I have said. I say this because *my* cable
TV was installed many years ago (1975 when the house was new) by the
local cable TV supplier and they put in a second ground rod for the
cable TV, that entered my house on the end opposite of all other
utilities ground rod. A few years ago they made a service call here to
bury some new coax, since the original coax that was installed by them
had degraded over time. All of our "utilities" come in underground. They
wanted to trench a new ground connection all the way from one end of the
house to the other to comply with the new "code". I wouldn't let them do
that because I didn't want them to tear up the yard and flower beds,
plus possibly damage my underground water sprinkling system. I had to
sign a waiver and was told if I took a "lightening" hit that came in the
house via the cable TV, that they would no longer be responsible for any
possible damage. So be it.
BTW, *all* of the grey colored phone "cable" I have seen uses solid
conductors, not stranded. About 18 gauge wire, I would guess. And
each pair of the wires are "twisted" inside the cable. Still the old
"twisted pair"! Do you know *why* they are twisted?
... Dew knot trussed yore spell chequer two fined awl mistakes.
--- PPoint 2.00
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