Abstract: A power supply control system of an installation including at least two devices having respectively electric circuits, e.g.

Abstract: A closed circuit interactive television system (10) provides a multichannel television signal from a localized head end (12 which is used for individualized interactive selections by a plurality of users (22, 24, 26). Each user station contains a conventional televison receiver (32a, 32b, 32c) and a smart box or interface and selection device (30a, 30b, 30c). The smart box interface and selection device (30) is disposed between the television receiver (32) and the RF distribution amplifier (36). The number of user stations (22, 24, 26) on the system (10) is virtually unlimited.