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Inventors
Application No. 09692554 filed on 10/19/2000
US Classes: 370/526 ,
Digital tone detection 370/352 ,
Combined circuit switching and packet switching 379/283 ,
Dual tone multifrequency (DTMF) receiver 708/312 ,
Tone detection 379/93.32 ,
Initial setup 379/386 ,
Signal receiver (e.g., tone decoder) 379/377 ,
Using line or loop condition detection (e.g., line circuit) 379/373.01 ,
Incoming call alerting 379/351 ,
Signalling integrity protection (e.g., voice signal immunity) 379/357.04 ,
Circuitry of call signal generator 379/418 ,
CALL SIGNAL GENERATING (E.G., RINGING OR TONE GENERATOR) 379/142.04 ,
Extracting call ID from transmitted signal 375/326 Carrier recovery circuit or carrier tracking
Examiners Primary:
Nguyen, Brian
Foreign Patent References WO 97/26753 WO 07/01/1997 WO 97/28628 WO 08/01/1997
International Class H04J 3/12
Abstract 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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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.
