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:
May. 17, 1977
Filed:
May. 19, 1975
R Fred Pfost, Los Altos, CA (US);
Eric G Breeze, Los Altos, CA (US);
Service Distributors, Inc., San Francisco, CA (US);
Abstract
A control system is described for activating a machine using magnetic signals encoded on a magnetic card, tape or equivalent member. The magnetic signals are pulse-width-modulated and, in one embodiment, also sawtooth-modulated. A means is provided which is responsive to the magnetic signals for generating a first and a second number. The first number corresponds to the number of times the magnetic card is usable for activating a machine. The second number is provided for identification and validation purposes. Means are also provided for reducing the number of times the card can be used each time it is used to activate a machine and for visually displaying that number on a visual display device. The use of skewed recording and reproduction heads is also described for improving signal discrimination and security against the usability of fraudulently produced magnetic cards.