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:
Apr. 19, 1977
Filed:
Dec. 29, 1975
Applicant:
Inventor:
Robert H Beeman, Berkeley, IL (US);
Assignee:
GTE Automatic Electric Laboratories Incorporated, Northlake, IL (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ;
Abstract
A parity checking circuit for use in multifrequency tone receivers is disclosed wherein associated receivers are made less susceptible to digit simulation when talking is present, by verifying that the same two tones are present for the entire parity timing period.