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. 13, 1979
Filed:
May. 26, 1977
Cordell V Castleman, Bloomington, MN (US);
Magnetic Controls Company, Minneapolis, MN (US);
Abstract
A circuit for detecting ringing signals on a telephone line in which the alternating voltage oscillations are converted to direct current pulses which are used to charge a first capacitor. Only signals of 14 hertz or above are sufficient to repetitively charge the first capacitor to a high enough voltage to open continuously a grounding circuit through a comparator, thus, allowing a second capacitor to charge up and open a second grounding circuit thus permitting current to flow to a suitable output. The output is used to activate lights on the telephone which lights are either flashed or winked by a unique resistance balanced solid state flash or wink generator.