GearOff - What packet size can you send reliably?
10/100 are the extremes, and I believe 100MB to be a pie-in-the-sky figure with perfect conditions.
Have you checked attenuation? Who made up the Cat 5 cables, or were they bought in?
Whgat about download speeds?
Just a few ideas.
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Me, sweat? I'm that cool, it's condensation.