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. 10, 1984
Filed:
Jul. 07, 1982
Applicant:
Inventor:
Gary Grantland, Hartselle, AL (US);
Assignee:
GTE Automatic Electric Inc., Northlake, IL (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ; 179 / ;
Abstract
In a telephone substation employing a dual tone multi-frequency signal generator, the common switch functions of disabling the transmitter and muting the receiver are performed by transistor devices responsive to a control signal produced by the signal generator. A bias voltage provided by the transistor device associated with the transmitter prevents dialing signals from reverse biasing the transistor device associated with the receiver and defeating receiver muting.