Power cutting device for terminal units of CATV system

• US 4,439,784 A
• Filed: 09/26/1980
• Issued: 03/27/1984
• Est. Priority Date: 09/26/1979
• Status: Expired due to Term

• Current Assignee: Pioneer Electronic Corporation (Pioneer Corporation)
• Original Assignee: Pioneer Electronic Corporation (Pioneer Corporation)
• Inventors: Furukawa, Hajime, Ohta, Yoshitsugu
• Primary Examiner(s): Martin, John C.
• Assistant Examiner(s): Coles, Edward L.
• Application Number:
  US06/191,206
• Time in Patent Office: 1,278 Days
• Field of Search: 358/86, 358/153, 358/190, 358/194, 358/210, 455/4, 455/5, 361/81, 340/825.07, 340/310 A
• US Class Current: 725/25
• CPC Class Codes: H04N 7/16 Analogue secrecy systems; Analogue subscription systems
• CPC Class Codes: H04N 7/17363 at or near the user terminal

Abstract

In a CATV system, power supplies of television sets associated with all terminal units are cut in response to an instruction contained in a down-data signal supplied by a central facility of the system. It is possible to cut the power supplies of the television sets, selectively and periodically, by incorporating address informations in the down-data signal.

Claims

1. In a CATV system in which a central facility is connected through cables to a plurality of terminal units so that various television programs are transmitted from the central facility through the cables to the terminal units, said television sets being supplied with power from a power supply, the improvement comprising a system for shutting off power to selected terminal units to insure that the selected terminal units can not be used, said system comprising:

a down-data transmitter provided in said central facility for periodically sending a down-data signal containing at least a power cutting instruction and an address number of said terminal unit, a down-data receiver provided in each of said terminal units for receiving said down-data signal and a power cutting device provided in each of said terminal units, said power cutting device being responsive to said data received by said down-data receiver to cut the power supply to said television sets when the address information contained in said down-data signal is coincident with its own address.

2. A system as claimed in claim 1 wherein said power switching means at each terminal comprises a power relay interposed between said power supply and said television set, and means responsive to receipt of said power cutting instruction for operating said power relay.

3. A system as claimed in claim 1 further comprising means at said central facility for periodically transmitting said down-data signal with said power cutting instruction and selected address numbers for periodically sending power disconnect instructions to selected terminals.