Rx Tx

•  a  different  type  of  cable  exists,  called  a ìcrossover cable. This type of cable internally crosses the TX and RX port on one end of the cable to the RX

and TX port on the other end of the cable, respectively.This type of cable allows two end Ethernet devices to communicate with each other when directly connected
as  a  point-to-point  network.
In  a  properly  configured  Ethernet  connection,  the  TX port  of  one  node  is  connected  to  the  RX  port  of  the other node, and vice-versa
an auto-crossover  capable  node  will  automatically  swap its  TX/RX  pins  between  TX  and  RX  until  a  link  is established. In this manner, either a crossover or patch
cable may be used with the node with the same results.It  is  only  necessary  that  one  node  in  a  linked  pair implement   auto-crossover.   Most   modern   switches,
routers, etc., implement auto-crossover.
http://ww1.microchip.com/downloads/en/AppNotes/01120a.pdf