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:
Oct. 24, 1978
Filed:
Jan. 31, 1978
Frederick J Glenn, Arlington Heights, IL (US);
Cook Electric Company, Morton Grove, IL (US);
Abstract
A loop extender is used in conjunction with a pair of telephone lines extending from a telephone central office to a subscriber location in order to insert a booster DC potential on the telephone lines in such a manner as to aid the flow of DC current produced on the telephone lines by a telephone central office battery. A control circuit has one input terminal coupled to one of the telephone lines and a reference terminal, another input terminal coupled to the other telephone line and the reference terminal, and an output terminal coupled to a relay. Whenever the input terminals are supplied with a specified potential from the telephone lines, an output from the output terminal maintains the relay in a nonenergized condition so that contacts controlled by the relay couple a DC booster power supply in series relationship with one of the telephone lines. In response to different potentials on the input terminals, the output at the output terminal energizes the relay such that the contacts insert the DC booster power supply in series relationship with the other telephone line. The DC booster power supply has a current sensor such that the booster DC potential is only supplied to the telephone lines when DC current is present on the telephone lines. In addition, the DC booster power supply has a current limiter limiting the amount of DC current on the telephone lines.