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:
Aug. 09, 1988
Filed:
Apr. 24, 1985
Applicant:
Inventors:
Bernard N Lipscher, Pittsburgh, PA (US);
Kevin G Coleman, Pittsburgh, PA (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
379 95 ; 380 23 ; 380 25 ;
Abstract
A computer security system employs a first telephone line for controlling a security unit which connects a second telephone line to the computer. Each authorized user must have a user security unit generating a control signal, such as an audio signal modulated by a pulse signal having a selectable pulse frequency, pulse duration and/or duration between pulses.