RJ45 interface is the most common twisted pair connector in Ethernet cables and networks. "RJ" means "registered jack", which is a standardized telecommunications network interface used to connect voice and data equipment to services provided by local exchange operators or long-distance operators. The physical connectors used by registered jacks are mainly modular connectors and 50-pin mini ribbon connectors.
RJ45 connector is an 8-position 8-contact (8P8C) modular plug and jack, usually used to connect a computer to an Ethernet-based local area network (LAN). RJ45 cable plugs usually consist of a plastic sheet and eight sockets. Four of these pins are used to send and receive data, and the other four are used for other technology or power network equipment.