Importance

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Abstract

A communications system comprising at least one exchange, television signal sources located at the exchange, subscriber's units each connected to the exchange by a respective direct communications link and provided with a television signal receiver, and selectors located at the exchange for selectively connecting the television signal sources to the communications links. The subscriber's units have transmitters for applying data signals to their respective communications links for transmission to the exchange to control the selectors and for transmitting general data to the exchange. The subscriber's units may each comprise two subscriber's stations each of which has a respective television receiver and data signal transmitter. Each subscriber's station is associated with a respective exchange-located selector controlled by that subscriber's station transmitter. Signals transmitted to the subscriber's stations are frequency division multiplexed, each subscriber's station receiver being tuned to receive a respective one of the FDM signals. Signals transmitted to the exchange are time division multiplexed under the control of a timing signal transmitted from the exchange, the exchange being responsive to the timing signal to identify the source of data signals received from each subscriber's unit.

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First Claim