Pioneer Electronic Corporation

Osamu Tazawa

Youichiro Tsuda

Masaki Saito

Tsuyoshi Fujiwara

Yoshifumi Saeki

Saburo Takaoka

Minoru Kosaka

Tsutomu Suzuki

Hiroki Uemura

Tsutomu Fukui

Sumitaka Matsumura

Takashi Morii

Toshihiko Hosaka

Shozo Nakamuta

Seiji Hashimoto

Tetuo Kanazashi

Katsuaki Matsumoto

Kuniaki Shiratori

Morihisa Oka

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. By employing both upstream and downstream messages which are initiated by a series of synchronizing bits and non-ambiguously related subsequent data sequences, and by the provision of means to initiate both downstream and upstream messages of short length without delay, rapid but reliable data interchange is effected despite differences in transmission and response times with different subscribers. Concurrently, terminal status and various special conditions including security alarms are remotely processed at each terminal, and short upstream messages are assembled containing priority selected data to be transmitted in response to an interrogation. The system incorporates additional means for monitoring power status, program selection and authorization and other operating conditions at each terminal effectively to provide accurate and reliable accounting information while preventing unauthorized or improper usage of restricted premium programs.

Interactive CATV system

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.

Method and apparatus for confirming transmission in bidirectional CATV

Growing community of inventors

Tokyo, Japan

Osamu Tazawa