SIGNAL SELECTION CIRCUIT

PURPOSE:To prevent the mixing of a noise from a opecified terminal by providing a connection circuit to be connected with a separator circuit to separate a down signal and an up signal amid a subscriber's line in an interactive CATV system, and providing a direct connection for down signals. CONSTITUTION:To a transmission line-side terminal 1 and to a subscriber's terminal-side terminal 2, respective down/up signal separation/combination circuits 3, 4 to separate/combine a down signal and an up signal are connected. These circuits 3, 4 function as a separator circuit or a combiner circuit. Also, the circuits 3, 4 come in virtual directly-connected status on the down signal-side. A down signal is first inputted to the transmission line-side terminal 1 then to the down/up signal separation/combination circuit 3 (this is equivalent to a down-up signal combination circuit). The signal further is inputted from said terminal to the down-up signal separation-commination circuit 4 (this is equivalent to a down-up signal seapration circuit), and from a common terminal, the signal is outputted to the terminal-side terminal 2.