SIGNAL DISTRIBUTION SYSTEM

摘要

A signal distribution system (200) is disclosed in which a programme source (204) is communicated via a transmission system (210) to a plurality of personal receiver units (220) which are configured to reproduce a signal derived from the source (204). The receiver units (220) each include a time unit store (23) containing a time unit value which, where greater than a predetermined amount, enables the receiver unit (22) to reproduce the signal. The time unit value is periodically decremented whilst the receiver unit (22) is in use until such time as the time unit value falls below the predetermined amount and the receiver unit is disabled. A vending system (202) is provided by which a user can purchase time units which are retained in the store (23) enabling further use of the receiver unit (220). A secure transmission arrangement (24) (fig. 10) and a transceiver apparatus (304) (fig. 13) are also disclosed.