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:
Oct. 16, 1990
Filed:
Apr. 04, 1988
Thomas G Berry, Schaumburg, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Subscriber units operating within a communication system are selectively addressed and required to solve a 'Puzzle' generated by a central device (controller) of a two-way communication system. The 'Puzzle' comprises one or more digital words and an operand, which provides instructions to the subscriber unit as to how to generate an answer. The subscriber units cannot anticipate either the occurrence nor the content of a particular 'Puzzle'. All subscriber units (both authorized and unauthorized) must return an answer to the 'Puzzle' or they may be denied access to the two-way communication system. Also, unauthorized subscriber units may be detected when the central device receives multiple answers to a 'Puzzle'.