Typically, using a splitter doesn't drastically affect your speed unless it degrades the signal, which is rare. Since cable is a shared medium, everyone in your building shares the connection, so the impact from one additional splitter should be minimal. An internet splitter, also known as an Ethernet splitter or network splitter, is a device that allows you to connect multiple devices to a single internet connection. The direct answer to whether this action reduces internet speed is yes, it typically does. When the signal is divided, the available bandwidth is also divided among the split signals.
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