In comp.dcom.cabling Jeff Liebermann <jeffl@cruzio.com> wrote in part:
> I enjoy asking the original questions backwards. In this
> case, it's "what would I have to do, to CREATE the problem"?

A good diagnostic method.

> At the time (about 1998), if you purchased any manner of pre-wired
> ethernet jumpers, you got EIA-568B wiring. Never mind that EIA-568A
> is the real standard. Well, my accomplice was working on his BICSI
> certification, and they were preaching EIA-568A.

Probably because the US government requires -A

> Never mind that I told him that I wanted the color coding to
> be consistent throughout the entire building, all of which
> was EIA-568B.

While US industry historically has been -B

> Careful here. That's not an endorsement for installing 2,000ft
> CAT5e runs. I once calculated the maximum cable length at
> about 1,200ft for 10baseT-HDX before timing becomes an issue.
> Why 2,000ft worked is still a mystery to me. It shouldn't have
> unless the timing on the ethernet devices is more relaxed than
> required.

10basedT has such relaxed timing because of the cascading
permitted. It became 100baseTX by tightening the circle.
Timing is mostly relevant for collision situations. If you
are isolated by a switch, how can it matter?

> Also, note that I was using 10baseT-HDX (half-duplex).
> Full duplex and/or 100baseT will not work due to collision
> domain issues and cable near end crosstalk.

Keeping crosstalk out is probably the main benefit.

> As for stretching the technology, I done my part:

I hope these installations have adequate lightening
protection!

> One of these days, I'll follow the standards and rules,
> but not this week.

That's fine when expertise is available for troubleshooting
and the reliability is acceptable.

-- Robert