Ethernet cable (Was: Sun3 valuations?)
Pete Turnbull
pete at dunnington.plus.com
Tue Jan 23 12:54:53 CST 2018
On 23/01/2018 16:48, Grant Taylor via cctalk wrote:
> On 01/23/2018 09:10 AM, Bill Gunshannon via cctalk wrote:
>> If you didn't locate the transceivers on those black marks you would
>> have had terrible performance as that affects collisions. Timing
>> (among other things like grounding) was very important with that
>> version of ethernet hardware.
>
> It's my understanding that the marks (black bands or other markings on
> the sheath) were exactly one wavelength apart. Which from what I
> remember ~> understand from my ham radio days is quite important.
No, that's quite wrong. The marks are every 2.5m (8.2 feet) wich IIRC
is 1/19th of a wavelength apart, the point being to try to minimise the
likelihood of connections being made where they'd suffer constructive
(additive) interference and to prevent transceivers being too close
together.
--
Pete
Pete Turnbull
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