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. 16, 1987
Filed:
Jul. 07, 1986
Paul E Crouch, Freehold, NJ (US);
Joseph J Nahas, Wyomissing Hills, PA (US);
Howard Ng, Old Bridge, NJ (US);
AT&T Technologies Inc. and AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
In an electronic coin telephone set, a fraud prevention arrangement prevents fraudulent coin tones originating at a telephone transmitter from being provided to a central office over a coin subscriber loop. The arrangement comprises a first and second transmission channel for alternately connecting the transmitter to the central office and also a fraud filter disposed in the second transmission channel. The fraud filter attenuates a selected frequency originating at the transmitter that is indicative of coin deposits. When coin deposits are not required by the central office, the transmitter is connected to the central office through the first transmission channel. When coin deposits are required by the central office, however, the arrangement connects the transmitter to the central office through the second transmission channel thereby avoiding the fraudulent generating of coin tones through the telephone transmitter.