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Jim Redelfs

In article ,
wrote:

I have 2 lines here and the few old sections of the original wiring
from the 60s had terrible crosstalk when you used both lines at the
same time. That really became obvious when you had a modem on one of
the lines.
I ended up rewiring the whole cludge with twisted pair to stop it

No doubt.

It's pretty simple: If there is crosstalk, the cable is made wrong.

Western Electric's old, light-olive gray D-Station wire (quad wire)
would NOT crosstalk even though it had very little twist. The red and
green conductors were across from - not NEXT to - each other. Likewise
for the yellow and black conductors. They were stacked like this if
viewed as a cross section:

red - black
green - yellow

This configuration prevented POTS crosstalk. The introduction of
Touchtoner and, later, dial-up modems, created some cross, but it was
usually only audible if the CUMULATIVE length of the quad was great.

Following divestiture, the big cable manufacturers (Rome, Cerro,
General, etc) saw a potentially huge, untapped market. They all jumped
on their looms and began cranking out UNTWISTED cable.

They never bothered to inquire of Western Electric or the incumbent
telcos as to how we got 300 people on a 400 pair cable yet they never
heard one another (crosstalk).

There was a period of about 7-8 years after Divestiture where virtually
all new construction was done with garbage wire.

This situation wasn't discovered by the homeowner until they added a
second line - right about the time that dial-up internet was coming on
strong. Suddenly, they reported HOOL (Hears Others On Line). It didn't
take long for us to figure out what was going on.

Heck, for the last twenty years of my career, I installed and maintained
the service to a true MANSION. It is a gated estate complete with
gargoyles and all the toys. During construction, the place was
independently wired with about two bucks-worth of crosstalk quad!!

Of course, this was insufficient from about day one as the owner (a VERY
successful businessman) peaked at about 5 lines and one FX (foreign
exchange) line. He also added a four-wire, high-speed data setup years
before there was DSL.

I installed two, multi-line SNIs on the outside of the huge home and we
"walked away" from the garbage wire inside. Independent phone
contractors dealt with the inside from that day on.

My favorite encounter there in later years was the independently
installed 6-pair station in the third-floor "cupola" room centered in
the middle of the roof - an island in the roof.

The "technician" bored a hole through a window sill, shoved out the
wire, climbed onto the roof and proceed with the installation. When
done, the 6-pair INSIDE cable lay across the sloped roof and ran down
the INSIDE of the downspout! At the bottom, the installer bored a hole
in the elbow near the SNIs, fished out the wire and connected it. I
never did learn how long that hack lasted. Not long, I'm sure.
--

JR