Voice and data exchange over a packet based network with DTMF
Patent 7082143 Issued on July 25, 2006. Estimated Expiration Date: October 19, 2020. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
370/526, Digital tone detection370/352, Combined circuit switching and packet switching379/283, Dual tone multifrequency (DTMF) receiver708/312, Tone detection379/93.32, Initial setup379/386, Signal receiver (e.g., tone decoder)379/377, Using line or loop condition detection (e.g., line circuit)379/373.01, Incoming call alerting379/351, Signalling integrity protection (e.g., voice signal immunity)379/357.04, Circuitry of call signal generator379/418, CALL SIGNAL GENERATING (E.G., RINGING OR TONE GENERATOR)379/142.04, Extracting call ID from transmitted signal375/326Carrier recovery circuit or carrier tracking
A method and system for detecting a dual tone in a composite signal having first and second components including means for separating the composite signal into its first and second components, means for estimating power of the separated first and second components, means for determining frequency of the separated first and second components, and means for comparing the power and frequency of the first and second components to at least one of a plurality of respective power and frequency thresholds to determine whether the composite signal comprises a dual tone.
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