An RJ45 jointer, also known as an RJ45 coupler, is a small device that allows you to connect two Ethernet cables together.expand_more This can be useful in a number of situations, such as when you need to extend the length of an Ethernet cable or when you want to create a temporary connection.

RJ45 jointers are relatively inexpensive and easy to use.expand_more They are simply inserted into the ends of two Ethernet cables, and they create a secure connection.expand_more However, it's important to note that using an RJ45 jointer can introduce some signal loss, so it's generally not recommended for permanent connections.expand_more If you need to extend the length of an Ethernet cable permanently, it's best to buy a longer cable.