Gigabit Ethernet uses four pairs per direction. It uses the same four pairs in both directions at the same time.
1000Base-T uses two pairs per direction, actually. It's full duplex. Each port sees two TX and two RX pair.
There are four pair of wires in the cable. If you use all of them for TX, you can't receive.
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1000Base-T uses two pairs per direction, actually. It's full duplex. Each port sees two TX and two RX pair.
There are four pair of wires in the cable. If you use all of them for TX, you can't receive.