Telephonic communications – Centralized switching system – Switching controlled in response to called station...
Patent
1997-10-29
2000-09-05
Kuntz, Curtis A.
Telephonic communications
Centralized switching system
Switching controlled in response to called station...
379 77, 379386, 327 39, 327 44, H04M 300, H04M 500
Patent
active
061154644
ABSTRACT:
A method and system for distinguishing valid DTMF signals from spurious DTMF noise includes detecting signals having a first signal component indicative of DTMF signals and having a second signal component having frequencies unrelated to DTMF frequencies. The second component is utilized in isolation from the DTMF frequencies of the first signal component. The analysis includes determining a signal level representative of the second signal component. If the signal level exceeds a predetermined threshold level, the first signal component is determined to be spurious noise. On the other hand, if the signal level is below the threshold level, the first signal component is passed to a DTMF-responsive system, such as a voicemail system or a voice response unit. Optionally, the operation includes requesting confirmation of the signal of interest, if the signal level of the second signal component falls within a range which includes the threshold level as its upper limit.
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Dunn Tave Pearce
Iglehart David
Kelly Daniel B.
Lester Leland
Kuntz Curtis A.
Siemens Information and Communication Networks Inc.
Tieu Binh K.
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