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:
Jun. 30, 1998
Filed:
Aug. 26, 1996
John S McGary, Huntsville, AL (US);
Barry C Zitting, Huntsville, AL (US);
Steven M Robinson, Madison, AL (US);
Adtran, Inc., Huntsville, AL (US);
Abstract
A ground fault detection and line power supply control system protects telecommunication service personnel working on line-powered telephone circuits from ground faults, without requiring that the line power supply be disconnected or shut down prior to a technician working on the line. A ground fault loop sensing current is sourced from an auxiliary DC voltage source that is separate and distinct from the line power supply. This auxiliary DC voltage source is coupled through a ground fault current sense resistor to one side of the powered line, so that detection of a ground fault condition is not dependent upon the supply of current from the potentially hazardous line supply. If a ground fault occurs through either or both of the powered lines, the current flow through the sense resistor will exceed a prescribed threshold, and initiate operation of a switching circuit within the line-powering equipment, thereby rapidly reducing power to the telephone line until the ground fault is cleared or the loop power supply is reset.