Ethernet splitters are an ideal option in home networks where there are fewer devices connected, typically, a maximum of two devices in one room. If you're content with a 100Mpbs connection and only have two devices to connect, then ethernet splitters are the best way to go.

Do Ethernet splitters affect speed?

While Ethernet splitters are cheap and appear to offer a good solution, they do result in a slower speed for network traffic. This is likely to affect the performance of your Ethernet-connected devices. Ethernet splitters are also limited to a maximum of two devices per cable.

Do Ethernet couplers reduce speed?

Ethernet couplers don't lower speed. They can cause more defective packets if the cable length is around 100 meters. An increase in defective packets reduces throughput because of packet re-transmission, but speed remains the same.