What pins do Ethernet NIC transmitters use?

Ethernet NIC transmitters utilize the pair connected to pins 1 and 2 to send data. This is aligned with the TIA/EIA-568 standard for twisted pair cabling, where pins 1 and 2 are assigned for transmitting data over a standard RJ-45 connector. In 10BASE-T and 100BASE-TX Ethernet, which use two pairs of wires from the cable, the first pair (pins 1 and 2) is designated for transmission, while the second pair (pins 3 and 6) is used for receiving.

Understanding the function of pin connections helps to establish proper network configurations and cable wiring standards, which are essential for ensuring reliable communication within Ethernet networks.