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. 21, 1999
Filed:
Jul. 21, 1997
Kirk E Shafer, Mission Viejo, CA (US);
Toshiba America Information Systems, Inc., Irvine, CA (US);
Abstract
Systems and method for monitoring and generating key pad status messages in a telecommunications network. A resistor ladder network is provided to generate distinct DC-level analog voltage signals in response to the pressing of any one of a plurality to keys of a key pad. A combiner circuit is employed to combine the DC-level analog voltage signals with an analog voice signal received from an audio transducer to form a composite analog signal, and a coder/decoder circuit is provided to convert the composite analog signal into a composite digital signal. A digital signal processing circuit executes a subtractive sample delta filtering algorithm to determine whether data indicative of a key press is included within the composite digital signal, and generates status messages indicative of a key press upon determining that a key has been pressed.