It is this standard that allows internet connection. This connector is physically compatible with the RJ11 connector if using an adapter.

On 10/100 Mbps RJ45 computer wiring, only 4 1~2 and 3~6 pins are used to transmit information.
In 1000 Mbps (1Gbps) transmission, the 8 socket pins are used.
Two RJ45 wiring standards are mainly common to wire the sockets : T568A and T568B.
These standards are very similar : only pairs 2 (orange, white~orange) and 3 (green, white~green) are changed.

The right cable (marked PATCH CABLE or STRAIGHT~THROUGH CABLE) is used to connect a device to a network hub or network switch.

RJ45 cross, definition :
The crossover cable (marked CROSSOVER CABLE) is usually used to connect two hubs or network switches.

The rJ45 links of the transmitter and receiver are reversed :

The transmission pair on one side is connected to the receiving pins on the other side.