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:
May. 10, 1994
Filed:
Jun. 12, 1992
Hiroyuki Ohta, Nagaokakyo, JP;
Masaaki Sugiyama, Nagaokakyo, JP;
Abstract
A sensor circuit for telephone line includes a detection coil (52) inserted in a telephone line (22). The coil generates a magnetic flux according to a line current which flows in the telephone line. A magnetic sensor (54) such as a Hall element generates a voltage signal in response to the magnetic flux. An output of the magnetic sensor is applied to a comparing circuit (58) and a tone deriving circuit (60) via an amplifier (56). The comparing circuit includes two comparators one of which compares the voltage signal from the magnetic sensor with a first reference voltage (V1) and the other of which compares the output signal with a second reference voltage (V2), so that a line current supervisory signal is outputted from the comparing circuit. The tone deriving circuit includes a band-pass filter and derives a tone signal from the voltage signal of the magnetic sensor. The line current supervisory signal and the tone signal are applied from terminals (46, 48, 62) to a signal processing circuit (36) by which a facsimile or a telephone set is selectively enabled.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile