3-way RJ45 splitter is a passive device that takes one Ethernet (RJ45) input and splits it into three separate outputs, allowing for the simultaneous, but not simultaneous-use, connection of three devices. It uses a single cable from a router or switch and divides its connection among three different Ethernet ports, but only one device can actively use the network at any given time. These devices are useful for extending network connections or in custom installations where splitting pairs for different signals is desired.