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:
Mar. 04, 1980
Filed:
Nov. 01, 1978
Applicant:
Inventor:
Robert J Sabon, Chicago, IL (US);
Assignee:
GTE Automatic Electric Laboratories Incorporated, Northlake, IL (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04B / ; H04M / ;
U.S. Cl.
CPC ...
179 / ; 179 / ; 179 / ;
Abstract
A circuit which detects the presence and absence of a telephone subscriber loop, before and after ringing current is applied to the loop. Coils functioning as magnetic field generating devices and a Hall effect device are used to perform the detection function. Inclusion of a capacitive shunt network limits the responsiveness of the Hall effect device during ringing, permitting use of the device on lines to which multiple ringers are connected.