Restrictive access control system
US4768229A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1986 |
| Grant date | Aug 30, 1988 |
| Priority date | — |
| Expiry date | Jul 21, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/162
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A restrictive access control system includes a 3-state switch for controlling the operating mode of the system and limiting tuning access to only designated channels. Tuning information is provided to a microprocessor via a control panel keyboard for storage in a nonvolatile memory and for subsequent recall therefrom when desired channel information is entered in the control panel by a viewer. In one embodiment, a 3-position key actuated switch has a first OFF position, a second PROGRAM position, and a third ON position. In the ON and OFF positions, the key may be removed from the switch while in the second PROGRAM position the key may not be removed from the switch. Programming of the nonvolatile memory may only be accomplished with the key in second PROGRAM position for storing either desired channels or locking out undesired channels. From the second PROGRAM position, the key may be turned to either the first OFF position for viewing all available channels or to the third ON position whereupon only authorized channels can be viewed. Turning the switch between the various positions, or modes of operation, is not possible without the key so as to provide a high level of viewing se…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.