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. 25, 1989
Filed:
Apr. 14, 1988
Applicant:
Inventor:
Claude Barraud, Paris, FR;
Assignee:
Schlumberger Industries, Montrouge, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379145 ; 379189 ;
Abstract
The invention relates to a system for mutual authentication between a transmission line and a terminal, e.g. a prepayment telephone set. The telephone (2) is connected to the line (14) via a monitoring device (18). Electronic circuits (18) and (12) are associated with the monitoring device and with the telephone in order to generate authentication frequency signals throughout the call at inaudible frequencies.
Barraud, Claude. (1989). Systeme d'authentification analogique reciproque entre un terminal et (U.S. Patent No. 4852155). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/4852155
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile