cat5 cable and 1000base-T question

In Mike Meyer's book, it states that the maximum rated speed for cat5 cable is 100Mbps. How is a 1000Base-T network able to transfer at 1000Mbps when it's using cat5 cable?

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bighornsheep

It uses all 4 pairs of wires for transfer instead of only the 2 pairs used in 100baseTX.

santoriilo

I think it uses Cat 5e and/or Cat6 for that speed.

vital

bighornsheep wrote:

It uses all 4 pairs of wires for transfer instead of only the 2 pairs used in 100baseTX.

So all cat5 cable comes in 4 pairs of wires and 100BaseTX uses only the 2/4? Why isn't the maximum rated speed of cat5 cable 1000Mbps then?

bighornsheep

vital wrote:

So all cat5 cable comes in 4 pairs of wires and 100BaseTX uses only the 2/4? Why isn't the maximum rated speed of cat5 cable 1000Mbps then?

Yes, all cat5 cables should be made with 4 pairs of wires (for noise-guards) but 100BaseTX will only use 2 pairs for transmit/receive. See this

1000Mbps is a data rate for the Gigabit ethernet technology and it basically says the NIC can put 1 billion BITS of data on the wire per second. It's a little bit more complicated than this in reality because there is channel utilization and noise to consider, but in essence, the end nodes and the transfer medium (wire) determine the data rate, that's why if you use a fastethernet card with Cat5, you only achieve 100Mbps, whereas with gigabit ethernet network cards using the same cat5 wire, you can achieve 1000Mbps or 1 Gbps.