Abstract: An arrangement for transmitting audiovisual information to one or more subscribers terminal from a server. Each subscriber terminal includes a storage unit. The server selects a transmission channel and/or transmission rate in accordance with a type of information to be distributed and/or other factors. The server then distributes the information on the basis of the selected transmission channel and/or rate. The system can cope with requests flooding from the subscribers without increasing the VOD service cost.

Abstract: A system and apparatus for transmitting audio and video information to one or more subscribers terminal from a server. Each subscriber terminal includes a storage unit. The server selects an information distribution scheme (unicast or multicast) and sends the information to the subscriber terminal(s). Each subscriber terminal receives the information in accordance with the selected information distribution scheme, and stores the information in the storage unit. The system can cope with multiple requests from the subscribers without increasing the VOD service cost.

Abstract: A two-way CATV system having a substantial number of terminals incorporates a central processor and transmitter system which continually interrogates the terminals at high speed, monitoring changes of usage of premium programs and other data while also permitting central control of access to restricted premium programs. For inexpensive but reliable intercommunication, short, fixed word length digital messages are frequency multiplexed onto the cable in both upstream and downstream directions, and subscriber groups are controllably selected in turn, with each subscriber being scanned in what may be an arbitrary order by transmission of unique private messages which are recognized at the terminal and in response to which previously prepared fixed length messages are immediately transmitted in return.

Abstract: In a bidirectional CATV system, in which interrogations and commands to terminals for individual subscribers occur at high speed, the status of individual terminals is checked rapidly and reliably without interfering with other transmissions. In response to diagnostic commands from the head end unit, the terminal responds with a message that is unlike the usual transmission, and identifies the status established in response to prior commands. The head end unit is thereby without delay able to ascertain not only that the prior commands were correctly transmitted and received but that the appropriate actions were taken in response thereto.