Jerry Stuckle wrote in news:m1gvg0$9v8$1@dont-
email.me:

One side note. Copper clad anything is not certified for any ethernet
cables. Even though ethernet runs at very high frequencies, only solid
or stranded copper is acceptable.


Telewest, who became Blueyonder, then after merging with ATL got bought by
Vitgin Media here in Britain, used copper clad steel cores. I don't know
enough to comment on their reasons, but it's definitely true, I just waved a
magnet at a few cables of theirs to prove it. My guess is that because the
lines were ostensibly for cable TV, they just coerced them into internet
wiring later. ADSL on the phone lines later beat them for speed, presumably
because the phones were using solid copper, but I'm not sure they used in the
external cables because I can't reach one right now.