RJ45, RJ11 and RJ12 connectors: What's the difference?

RJ45, RJ11 and RJ12 connectors: What's the difference?

When wiring networks or telephones, choosing the right connector is crucial. RJ45, RJ11, and RJ12 connectors look similar, but they are designed for different uses.

The RJ45 connector is the standard for Ethernet networks. It is the largest of the three, with eight pins, and is used with twisted-pair cables (such as Cat5e or cat6) to connect computers, routers and switches for high-speed data transmission.

The RJ11 connector is commonly used for landline telephone connections in homes. It is smaller than the RJ45 and typically has six positions, but only two or four wires (pins). It is designed for voice communication.

The RJ12 connector is similar in size to the RJ11, but uses all six positions and pins. It is often used in telephone systems for business environments, for example, to connect desk phones to a private branch exchange (PBX).