RJ-45 Connectors and RJ-45 Ports Explained

An RJ-45 connector connects one end of the Ethernet cable to an end device having an RJ-45 port. It is a small block of plastic with eight metal contacts.

Which cable uses RJ-45 connectors?

In an Ethernet network, we use twisted pair cables to connect end devices. A twisted pair cable has two endpoints and eight copper wires inside it. It joins two end devices. It uses an RJ-45 connector at both ends.

There are two types of twisted pair cables: STP and UTP. Both types have eight copper wires twisted in four pairs. The main difference between both types is UTP wraps all wire pairs with a single plastic outer cover, while STP wraps each pair with additional foil paper inside the cable.

STP and UTP cables

To learn more about STP and UTP cables, you can check the following tutorial.

STP and UTP cables Explained

Both cable types use RJ-45 connectors at both ends to connect the cable to end devices.

RJ 45 connector on stp and utp cables

Types of RJ-45 connectors

There are two types of RJ-45 connectors: male and female. A twisted cable uses male connectors at both ends. End devices use female RJ-45 connectors.

A female RJ-45 connector is also known as an RJ-45 port. Devices that connect with a computer network (such as computers, laptops, printers, and servers) or provide connectivity in a computer network (such as routers, switches, hubs, and repeaters) have RJ-45 ports. RJ-45 ports are also known as Ethernet ports.

End devices such as printers, laptops, servers, and computers usually have one or two RJ-45 ports. Generally, these ports are integrated into the device's motherboard and are known as onboard ports. If you need more RJ-45 ports on an end device, you can install additional RJ-45 ports on it.

on board RJ 45 port

If you want to connect more than two end devices, you need a central device such as a hub and switch. A central device has many RJ-45 ports. Each port connects an end device to the network.

RJ 45 port on a switch

Differences between RJ-11 and RJ-45 connectors

An RJ-11 connector looks similar to an RJ-45 connector but they are different.

rj 45 and rj 11 connectors

RJ-11 connectors are used to connect telephone wires while RJ-45 connectors are used to connect twisted pair cables in a computer network.

The RJ-11 connector uses a 6-position, 2-contact (6P2C) interface for one-line telephone services.

The RJ-45 connector uses an 8-position, 8-contact(8P8C) interface for Ethernet networks.

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