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:
Dec. 16, 1980
Filed:
Mar. 01, 1979
Applicant:
Inventors:
Assignee:
GTE Automatic Electric Laboratories Incorporated, Northlake, IL (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ; 328 27 ; 3403 / ; 179 / ;
Abstract
A telephone ringing signal generator which produces a signal that can ring a plurality of connected ringers tuned to different frequencies. The ringing signal comprises sequentially varying frequencies and each ringer will ring in response to its particular frequency. A counter is used to define the duration of the ringing signal and enable each frequency sequentially. A variable sweep frequency oscillator is connected to the counter and generates a signal having a different frequency for each counter increment. A programmable filter shapes the signal into a sine wave which is amplified to ringing voltage levels by a ringing signal amplifier.