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:
Feb. 04, 1992
Filed:
Jan. 15, 1991
Claude Barraud, Brussels, BE;
Jean-Loup Poilleux, Vanves, FR;
Christian Guion, Verrieres-le-Buisson, FR;
Schlumberger Industries, Montrouge, FR;
Abstract
The invention relates to a prepayment indoor telephone in which payment is performed by means of memory cards. In order to make the use of the telephone set (104) secure, a verification module (110) is connected to its telephone line (130) in the vicinity of the exchange (102). The verification module (110) and the telephone (104) periodically generate two respective versions of authentication information and these two versions are compared in the verification module (110). Authentication takes place only if the card reader (128) has delivered a signal indicating that the required telephone charge has been paid.