Couplers, also known as a taps, are used to place multiple broadcast antennas in a long line when installing a cell phone signal booster system.
Diplexers implement frequency domain multiplexing, which splits high and low frequencies through different channels back into one port.
Splitters allow 2-4 indoor antennas to be used with one cellular signal booster. Bi-directional splitters distribute equal amounts of signal to similarly sized areas.