| 摘要 |
PURPOSE:To obtain an economical video selection controller by using a telephone circuit as a transmission medium for a program selection control signal from a subscriber's house to a program switching center, and making said signal be out-of voice band signal. CONSTITUTION:To select a desire video, the channel selection button of a video selection operating device 10 is depressed, so that a signal inherent to the selected channel is modulated with the out-of band signal then transmitted to a branching/inserting circuit 13. In the circuit 13, the out-of voice band signals transmitted from the device 10 to the telephone circuit are superimposed. Thus superimposed signals are branched again by the branching/inserting circuit 13 on the telephone exchange-side, and transmitted to a control circuit 11. The circuit 11 extracts a necessary channel selection signal from the superimposed signals, and by the extracted signal, a selection circuit 6 is controlled to select a desired video source 1. Hence, a telephone call is not unfavorably influenced.
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