RJ is the abbreviation of Registered Jack, which means "registered jack". In FCC (Federal Communications Commission Standards and Regulations), RJ is an interface that describes a public telecommunication network, and RJ45 of a computer network is a common name for a standard 8-bit modular interface. RJ45 is a common network cable interface, also called crystal head, which is usually connected to the network card. RJ45 is a kind of information socket (ie, communication terminal) connector in the wiring system. The connector consists of a plug (connector, crystal head) and a socket (module). The plug has 8 grooves and 8 contacts.
RJ45 connectors provide ruggedized equipment and IP20-IP67 degrees of protection. No tools are required, the time is significantly shortened, and the cost can be reduced very well.