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:
Jul. 09, 1996
Filed:
Jun. 28, 1995
Masaaki Sugiyama, Nagaokakyo, JP;
Hiroyuki Ohta, Nagaokakyo, JP;
Abstract
A sensor circuit for telephone line (10) includes a detection coil (12a) inserted in a telephone line (14). The coil generates a magnetic flux according to a line current which flows in the telephone line. A magnetic sensor (12b) such as a Hall element generates a voltage signal in response to the magnetic flux. An output of the magnetic sensor is amplified by an amplifier (16). A calling signal detection circuit (18) which receives an output of the amplifier includes a capacitor (20) for cutting-off a direct current component included in the amplified output. An alternating current component is inputted to a (-) input of a hysteresis comparing circuit (22) which receives a reference voltage (Vref1) at a (+) input thereof. Therefore, the alternating current component is converted into a pulse signal which is then withdrawn at an output terminal (34) as a calling signal for ringing a bell of a telephone set. In addition, a line current supervisor circuit (36) is connected to the output of the amplifier so as to detect the line current by utilizing reference voltages (Vref2, Vref3).
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile