The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 15, 1986
Filed:
Oct. 19, 1983
William L Thomas, Libertyville, IL (US);
Zenith Radio Corporation, Glenview, IL (US);
Abstract
The present invention permits a teletext system operator to adjust subscriber access to service levels individually by adjusting a code at the head end station. A head-end station transmits a tier description page and a tier authorization page. The tier description page divides the data base into a group of tiers each comprising a defined range of pages. The authorization page lists authorization codes for all subscribers, one code per subscriber. Each subscriber station includes a permanent location code. When access is requested by the subscriber, the subscriber station uses the location code to acquire the authorization code transmitted by the head-end station. The authorization code indicates which tiers the subscriber station may decode. To change the service, the system operator may change the authorization codes at the head-end station or change the range definitions for the service level tiers.