Well, IIRC, you could run 10Base-T over 2-pair Cat 3, and even fast ethernet over 1 version of 2-pair Cat 5, so maybe the Cabletron is more lenient to pre-Cat 5 10Base-T and allowed the maybe-not-wired-to-4-pair-EIA-Cat-5 cable to work where the 3Com wouldn't.


You can run 100mbs over cat 3 if the conditions are right. Both 10 and 100 only use 2 pair. One pair is positive/negative transmit, one positive/negative receive. The differences in cat3 and cat5 are in the twisting, predominately. The other two pair can be used for voice, if you wish... Not much reason to do so, now, but it can be done.

The fun thing you can do with 10 and 100baseT is just hooking up the receive pair. Then you can use that cable as a damn near undetectable sniffer with a promiscious ethercard... No other machine on the net is going to be able to pick it up.... which the right software can do to a normal sniffer. Not a HELL of a lot of use, but it has came in handy once here.

10mbs will run on just about anything. I've got a plant, that I inherited mind you, that has 50% or more of it's network running on 2 pair of cable, loose, unjacketed, no twist... nada. It's fuglin uckly. It's also getting rewired, but it does, surprisingly, work as is.

My guess is that the cable had a pin off, or was a crossover cable, and the cabletron detected and corrected. How, or why, I don't even want to know.

and the false economy of building cables in-house to "save money"

The Funny thing is... I have a hard time agreeing with this. It's a pain in the ass to do, but I'll trust my cables a hell of a lot more than the prebuilts. I primarily use pre-builts, but whenever there is a possible cabling issue, I'll crimp my own to make sure. Now, I've got a hell of a lot of experience in doing these, and don't recommend just anyone doing it, but......

Now, thinking about it, I don't trust anyone else's in-house cables, so maybe...

Of course, buying ANYTHING at Rat Shack is dubious....