In comp.dcom.cabling Jeff Liebermann <jeffl@cruzio.com> wrote in part:
> On Sat, 03 May 2008 20:22:07 GMT, Robert Redelmeier
>>These homebuilt cables, which wiring pattern did you use?
>>T-568A or -B ? If you don't know what I'm talking about,
>>it is highly likely you split a pair.
>
> Huh? Unless he did something really disgusting, like EIA-568A on one
> end and EIA-568B on the other, either wiring standard will work. The
> color codes are different, but the pairing is identical.

Oh yes, fully agreed. But I think it relatively unlikely
the OP would have followed either without some awareness.
I'm testing for that awareness.

The intuitive wiring patterns (SBS and USOC) will split a pair.
All the correct ones are somewhat counter-intuitive.

> Drivel: I once had some hired help in wiring a medical
> office. I did 568B while my hired help did 568A wiring.
> Nothing worked when we were done. Never ignore the obvious.

Easier to notice and fix with jacks.

> True. I recently demonstrated that I can run 10baseT-HDX (half
> duplex) through 2,000 ft of CAT5e (two rolls in series), without any
> data degradation. If I had a 3rd roll, I would have added it. The
> catch is that it would only work between my Cisco 1900 ethernet
> switch, and a desktop with an Intel Pro100 card. It would function to
> other devices (several laptops, assorted junk around the office), but
> these showed various errors in the switch SNMP logs.

Nice data point.

-- Robert