Our 2.4GHz systems have four channel capabilities meaning up to four different video transmissions can be run simultaneously. One transmitter will be needed for each video source and a corresponding receiver will be needed for each transmitter if one wants to watch all signals simultaneously. Its recommended to limit simultaneous transmission to two channels when possible because you may experience ghosting effects (bleeding of channels) when running four signals at once. The ghosting effect is due to the very narrow band allocated for 2.4GHz use. The ghosting effect can be avoided when running two signals by spacing the channels apart (e.g., Ch1 and Ch 3).