RJ45 (Registered Jack 45) is a physical interface often used for terminating twisted pair type cables. "RJ" stands for Registered pack which is part of theUnited states Code of Federal Regulations. It has eight "pins" or electrical connections per connector.
It is frequently terminated using the T568A or T568B pin/pair assignments that are defined in TIA/EIA-568-B:
RJ45 is connector and a socket. The socket is inbuilt port on the hardware machine (Computer or laptop) seems like as telephone or modem socket. It is used to connect Network cable. Network Cable contain RJ45 connector on both side. Source: CoolInterview.com
RJ-45 is the standard connector utilized on 4-pair (8-wire) UTP Unshielded Twisted Pair) cable. It is generally implemented for network and telephone cabling. Sometimes, it's also utilized for serial network connections.
The RJ-45 connector is the standard connector for 10Base-T/100Base-TX Ethernet, ISDN, T1, and modern digital telephone systems. Standard RJ-45 pinouts describe the arrangement of the individual wires required when connecting connectors to a cable. RJ-45 connectors appear similar to the RJ-11 connectors utilized for connecting telephone equipments, but they are a bit wider.