HELP: External 250G USB screwed with GParted
Mikkel L. Ellertson
mikkel at infinity-ltd.com
Mon Jan 21 17:31:00 UTC 2008
Craig White wrote:
> it seems that you are ignoring the reality that Cat 3 cables (10Base-T)
> are physically different than Cat 5 cables. Cat 3 cables needed only 4
> wires and Cat 5 cables needed 8, thus expecting a Cat 3 cable to work
> properly at 100Base-T is not realistic at all. This of course ignores
> the different twisting requirements for shielding.
>
I could have sworn that the CAT 3 cable I used for networking was 4
pair, and not 2 pair. I can remember some 2 pair cable use for POT
connections, but every networking application was 4 pair. Now, both
10BaseT and 100BaseTx only use 2 pair, but the cable is normally 4
pair. Now, there is a difference a physical difference between CAT 3
and CAT 5, but it has more to do with how the pairs are twisted
together then the number of wires. The number of wists/inch, and the
relationship between the number of twists in each pair change the
electrical characteristics of the cable. (Each pair has a different
twist rate.) I think how the pairs are twisted together in the cable
is also specified.
What gets interesting is that with the proper test equipment, you
can detect the different twist rate of the cable, the total length,
any connections in the run, and even sharp bends in the cable. You
can also tell the difference between CAT 3 and CAT 5 cable. I have
to admit that the equipment that does this is a lot more expensive
then a simple pair tester, but when you have to certify an
installation, it is necessary. (cable length, noise level,
crosstalk, etc...)
Mikkel
--
Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: OpenPGP digital signature
URL: <http://listman.redhat.com/archives/fedora-list/attachments/20080121/7c5a433a/attachment-0001.sig>
More information about the fedora-list
mailing list