| 摘要 |
The device comprises, within each subscriber's terminal, a carrier wave generator which carries said wave to a distribution centre (1) as long as the television of the terminal is in operation, the absence of said wave being detected in the centre by a circuit (4) which thereupon assigns a phantom channel to the subscriber. The switching of the subscriber's television to an independent source of the centre can only be accomplished following the assignment of the phantom channel to the subscriber. |
