[rescue] Rescued Sun servers, now what?!
saquinn624 at aol.com
Mon Feb 20 20:05:42 CST 2012
>for odd historic telephone reasons, the pairs
>aren't always run to adjacent pins. 568b started life out as part of
>at&t pds [premises distribution system], which was naturally used for
>starlan-1, the twisted pair ancestor of 10bt and 100bt.
Not at all odd - in fact the old telephone system makes perfect sense. The
connectors were wired moving out from the center, so the center two connectors
were "line 1", the next two connectors symmetrically out from the centerline
were "line 2" and so on. This way you can plug a "single-line" telephone into
a 4-line system and still have it work fine (as long as you were fine with
line 1), instead of needing to find an adapter cable.
It was eliminated because of crosstalk problems when you started transmitting
data at higher rates.
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