Ethernet Cable Identifcation Error... 1

[13tuba]

Question of the day: What causes some computer not to recognize an cat5 ethernet cable with the typical rj25 connector while yet other computers have no problem with it? Further more, an identical cable will work with both computers?!

This problem has been frustrating both my father and myself for a little over a month now. We've found a few computers (both old and new - the new one being a dell so who knows there) that have the above described problem. To be more specific about it, the computer doesn't even detect that the cable is plugged in most of the time. I believe at one point one of the computers I've been having this problem with recognized that it was connected to a cable but got the "limited connectivity" warning etc from Winxp pro. My father solved this problem at his workplace by simply swapping cables, but in my particular case, one of the computers in my room thats just not an option unless i happen upon a nice helping of extra cat5 lying around again.
( *whistle*, finding 500 feet of scrap cat5 while their wiring the hospital is quiteeeeeee nice )

I at the moment do not have a cable tester of any sort and would generally like to avoid that option as i do not make these cables regularly, only every now and again in a blue moon.

I personally thought it was just a bad crimp on my part so I re-crimped the sucker and yet again have the exact same problem - my laptop works with the cable just fine, this particular desktop doessss not.
Thanks kindly for your time and ideas!
Karl

 

[edfair]

I've generally found these types of problems to be issues within the RJ45 socket on the NIC or with the seating of the contact pins in the plug. Anything that would keep the wire in the jack from pressing down or making contact with the contact pins.
My most recent one involved a patch-panel plug that wouldn't make contact unless it was rotated CCW to the limits of play as it was inserted. As soon as the pressure was released it lost contact. It worked fine with all the other systems.

 

[technome]

To add to causes of connectivity issues...
Not maintaining the wire twist at the RJ45 plug or socket

Using subgrade wire, PVC is far more troublesome than Teflon cable

Lint in the RJ45 socket.

Corrosion near seaboard areas.

Kinked/stretched wire.

Different NIC models vary in sensitivity to wire/termination issues. Intel NICs are one best, Broadcom of the worst

Using a cable tester which can certify to CAT specs is the only way to go, cheaper cable testers only check wire pairs and check for continuity, half the battle.

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Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm