RJ45 is a connector for an information socket (ie, a communication socket) in a cabling system. The connector consists of a plug (connector, crystal head) and a socket (module).

    The plug has 8 grooves and 8 contacts. RJ stands for Registered Jack, which means "registered socket." In the FCC (Federal Communications Commission Standards and Regulations), RJ is the interface that describes public telecommunications networks, while RJ45 in computer networks is often referred to as a standard 8-bit modular interface.