Ethernet RX and TX connections
There are two pin arrangements known as "MDI" and "MDI-X" the convention is that end devices are MDI while hubs and switches are MDI-X.

https://en.wikipedia.org/wiki/Medium-dependent_interface#MDI_vs._MDI-X

However most modern equipment has "AUTO-MDIX" which automatically swaps the transmit and receive pairs if needed so you generally don't have to worry too much about this anymore.