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[SOLVED] Ethernet Cabling

This is a discussion on [SOLVED] Ethernet Cabling within the Cabling and Network Cards forums, part of the Tech Support Forum category. CAT-5 cable is four pairs. A typical computer uses only two pairs. What is the logic behind every Ethernet cable


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Old 02-22-2009, 01:30 PM   #1
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CAT-5 cable is four pairs. A typical computer uses only two pairs. What is the logic behind every Ethernet cable having two unused pairs? Spares?

Is there any reason not to use pairs three and four for a second computer? Because the pairs are adequately twisted, crosstalk is not a concern.

While I understand redundancy, the idea that most Ethernet networks have twice the copper that is necessary, I don't think I understand the logic behind four pairs being used when only two pairs are necessary. Maybe, at the time the spec was written, someone thought that four pairs would be necessary for future applications.
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Old 02-23-2009, 08:19 AM   #2
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Gigabit uses all four pairs, but if you have 100mbit connections, there are splitter adapters to allow you to connect two connections at each end, you are correct in yoru assumptions.
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Old 02-23-2009, 08:30 AM   #3
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I did not realize that Gigabit uses four pairs. That certainly answers the question!
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