What is RJ-45 Connector and What is it's purpose?

Tell me about RJ-45 connector and for what purpose this connector is used in local area network of star topology?

The RJ45 connector (RJ stands for Registered Jack) is one of the main connectors used with Ethernet network cards, and transmits information over twisted pairs of wires. For this reason, it is sometimes called an Ethernet port. For more detail kindly visit following link

http://www.webopedia.com/TERM/R/RJ_45.html