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:
Jan. 28, 1986
Filed:
Aug. 23, 1984
David M Embree, Reading, PA (US);
David C Goldthorp, Reading, PA (US);
Howard H Longenecker, Indianapolis, IN (US);
David R Vogelpohl, Indianapolis, IN (US);
AT&T Technologies, Murray Hill, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
An electronic tone ringer provides a distinctive ringing capability through the use of two oscillators which allow selection of four tones and four modulation rates. In determining the type of tone generated, formattable inputs select between frequency shift or amplitude modulation modes or disabling the modulation altogether to generate a single tone. In the frequency shift mode, two fundamental frequencies are generated which are related by a predetermined ratio, the output tone alternating between these two frequencies at one of four selectable modulation rates. In the amplitude modulation mode, a single frequency is switched on and off at the selected modulation rate. All of the tones are produced with a duty cycle appropriate for driving an electromagnetic acoustic transducer.