EP0319282A2
Expired / Lapsed
EP
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A voice mail system with improved detection and cancellation
Assignee: Cobotyx Corp Inc
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Filing: 1988-11-30
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Granted: —
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Expires: 2008-11-30
Abstract
Abstract A voice mail system (10) includes method and apparatus for muting a previously recorded audio signal upon detection of a DTMF signal to differentiate between recorded DTMF signals and valid DTMF commands. A DTMF signal detected after muting is recognized as an invalid command. The system (10) also includes method and apparatus for matching the impedance of a 2-to-4 wire converter (94) within the system (10) against the impedance of the outside telephone system (14) to improve the ability of the system (10) to detect the DTMF commands generated by a caller. Other features of the voice mail system (10) comprise apparatus for detecting the end of a message by recognizing call progress tones. The system also includes a message board in which each user of the system (10) can check its status and whether the user has a waiting message.
Inventors
- 👤 Dennis J. O'brien
- 👤 Paul G. Hanson
- 👤 Thomas D. Klarquist
- 👤 Bruce C. Nepple
- 👤 Michael C. Park
- 👤 Robin R. Rosas
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 22:29
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/42; H04M3/50; H04M3/53; H04M3/533
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
202 words
In a voice mail system (10) having a source for playing back a previously recorded audio message, apparatus for differentiating between a recorded DTMF signal recorded in the audio message and a user-generated DTMF signal, comprising: a tone detector (96) for detecting DTMF signals and generating a tone, the tone detector (96) having means for generating interrupt signals along with the detected tone to indicate the tone's presence, the tone detector further including means (120, 122) for requiring the detected tone to persist for a predetermined time before generating the interrupt signal to prevent transients from prompting the generation of said interrupt signal; a switch (98) coupled between the source of the recorded audio message and the tone detector (96); and computer means (24) receiving the detected tone and responsive to the interrupt signal for determining if the DTMF signal producing the tone is a valid command, the computer means controlling the switch (98) to interrupt the transmission of the recorded audio message to the tone detector (96) for a predetermined time, determining if the tone is still present during the predetermined time, and recognizing a tone as a valid command if still present and ignoring the tone as invalid if absent.
Claim 2
Dependent Claim
202 words
In a voice mail system (10) having a source for playing back a previously recorded audio message, apparatus for differentiating between a recorded DTMF signal recorded in the audio message and a user-generated DTMF signal, comprising: a tone detector (96) for detecting DTMF signals and generating a tone, the tone detector (96) having means for generating interrupt signals along with the detected tone to indicate the tone's presence, the tone detector further including means (120, 122) for requiring the detected tone to persist for a predetermined time before generating the interrupt signal to prevent transients from prompting the generation of said interrupt signal; a switch (98) coupled between the source of the recorded audio message and the tone detector (96); and computer means (24) receiving the detected tone and responsive to the interrupt signal for determining if the DTMF signal producing the tone is a valid command, the computer means controlling the switch (98) to interrupt the transmission of the recorded audio message to the tone detector (96) for a predetermined time, determining if the tone is still present during the predetermined time, and recognizing a tone as a valid command if still present and ignoring the tone as invalid if absent.
Claim 3
Dependent Claim
161 words
In a voice mail system (10) employing 2-to-4 wire converter means (94) for adding a previously recorded audio signal to a received audio signal and then cancelling the previously recorded audio signal so that only the received audio signal passes through the converter means for recording, a method of matching the impedance of the 2-to-4 wire converter (94) to the impedance of the telephone system (14) providing the received audio signal, comprising: selecting one of a plurality of cancellation networks (86-92) each having a different impedance for connection to the 2-to-4 wire converter means (94); generating a test tone on a recorded audio message; detecting the audio signal passing through the 2-to-4 wire converter means (94); repeating the steps with each of the other of the plurality of cancellation networks (86-92); and evaluating the strength of the detected audio signals to determine the cancellation network that best matches the impedance of the 2-to-4 wire converter means (94) to the telephone system.
Claim 4
Dependent Claim
161 words
In a voice mail system (10) employing 2-to-4 wire converter means (94) for adding a previously recorded audio signal to a received audio signal and then cancelling the previously recorded audio signal so that only the received audio signal passes through the converter means for recording, a method of matching the impedance of the 2-to-4 wire converter (94) to the impedance of the telephone system (14) providing the received audio signal, comprising: selecting one of a plurality of cancellation networks (86-92) each having a different impedance for connection to the 2-to-4 wire converter means (94); generating a test tone on a recorded audio message; detecting the audio signal passing through the 2-to-4 wire converter means (94); repeating the steps with each of the other of the plurality of cancellation networks (86-92); and evaluating the strength of the detected audio signals to determine the cancellation network that best matches the impedance of the 2-to-4 wire converter means (94) to the telephone system.
Claim 5
Dependent Claim
27 words
The method of claim 2 including selecting each tone from a plurality of tones across a frequency range of tones normally received in the telephone system (14).
Claim 6
Dependent Claim
25 words
The method of claim 2 including varying the amplitude of the selected tone across a range of amplitudes normally received in the telephone system (14).
Claim 7
Dependent Claim
138 words
In a voice mail system (10) employing a 2-to-4 wire converter means (94) for adding a previously recorded audio message to a received audio message and then cancelling the recorded message so that only the received audio message is recorded, an apparatus for matching the impedance of the 2-to-4 wire converter means (94) to the telephone system once the received audio message arrived, comprising: a plurality of cancellation networks (86-92) providing a range of impedance; switch means (84) for connecting each cancellation network to a 2-to-4 wire converter means to change the impedance of the converter means; means (24) responsive to the received audio signal passing through the converter means for connecting each cancellation network to the 2-to-4 wire converter means to reduce the previously recorded audio signal and thereby best match the impedance to the telephone system.
Claim 8
Dependent Claim
138 words
In a voice mail system (10) employing a 2-to-4 wire converter means (94) for adding a previously recorded audio message to a received audio message and then cancelling the recorded message so that only the received audio message is recorded, an apparatus for matching the impedance of the 2-to-4 wire converter means (94) to the telephone system once the received audio message arrived, comprising: a plurality of cancellation networks (86-92) providing a range of impedance; switch means (84) for connecting each cancellation network to a 2-to-4 wire converter means to change the impedance of the converter means; means (24) responsive to the received audio signal passing through the converter means for connecting each cancellation network to the 2-to-4 wire converter means to reduce the previously recorded audio signal and thereby best match the impedance to the telephone system.
Claim 9
Dependent Claim
75 words
In a voice mail system (10) having means for receiving an audio message to be recorded, apparatus for detecting the end of a message, comprising: call progress tone detecting means (102) for detecting call progress tones generated by a telephone system (14); and means (24) responsive to the detecting means (102) for causing the voice mail system (10) to hang up and terminate the call upon detection of call progress tones for a predetermined time.
Claim 10
Dependent Claim
75 words
In a voice mail system (10) having means for receiving an audio message to be recorded, apparatus for detecting the end of a message, comprising: call progress tone detecting means (102) for detecting call progress tones generated by a telephone system (14); and means (24) responsive to the detecting means (102) for causing the voice mail system (10) to hang up and terminate the call upon detection of call progress tones for a predetermined time.
References Cited (Backward Citations)
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