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:
Dec. 02, 1986
Filed:
Sep. 27, 1984
Johann D Ramsaran, Carleton Place, CA;
Bora Biray, Nepean, CA;
Nadir Nizamuddin, Calgary, CA;
Anthony Yung, Calgary, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
The invention provides a circuit and method for the time-sharing of a DTMF tone receiver. A DTMF receiver has its input terminal connected to a common output terminal of a pair of transmission gates, each gate having an input terminal connected to a respective source of DTMF signals. A control circuit provides switching signals to the transmission gates to cause their input terminals to be connected alternately to the input terminal of the receiver at a predetermined rate until the receiver detects a tone signal on at least one of the input terminals of the gates. The control circuit includes circuitry responsive to the initial tone detection for inhibiting the further generation of switching signals until the tone detection by the receiver has been completed.