DTMF Tone Attenuation in Telephone Sets
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Solution Overview
Problem
The loudness and variability of dual-tone multiple frequency (DTMF) dialing confirmation tones in telephone sets can be annoying to users and disruptive in quiet environments, especially during continuous operations like remote access applications.
Innovation Solution
A method and apparatus that attenuate or mute DTMF dialing confirmation tones by receiving an enable signal from a tactile user input device, generating DTMF tones, and communicating them to a telephone line with a predetermined signal level reduction, allowing the attenuated tones to be sent to an audio output device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dialing confirmation tones are generated at normal volume levels, then users can confirm key presses clearly, but users experience annoyance and disturbance in quiet environments
Solution Approach 1:
The patent implements a switchable attenuation mechanism that dynamically adjusts the volume level of dialing confirmation tones based on user preference. The system transitions from a fixed-volume design to a dynamic one where the confirmation tone volume can be attenuated by a predetermined amount (e.g., 20-40 dB) when an enable signal is received, allowing users to eliminate annoyance while preserving the ability to confirm dialing when needed.
Solution Approach 2:
The patent changes the acoustic parameter (volume level) of the dialing confirmation tones by applying signal attenuation. The confirmation tone generator produces tones at normal levels, but an attenuator component reduces the amplitude by a predetermined amount when activated, thereby transforming the harmful loud tones into acceptable low-volume tones without affecting the dialing functionality.
2Object-affected harmful factors
If dialing confirmation tones are attenuated to reduce annoyance, then user comfort is improved, but dialing confirmation may become imperceptible
Solution Approach 1:
The patent applies partial attenuation rather than complete silencing of the confirmation tones. By attenuating the signal by a predetermined amount (e.g., 20-40 dB) rather than reducing it to zero, the system maintains residual audibility of the confirmation tones while sufficiently reducing their volume to eliminate annoyance in quiet environments. This partial action preserves the essential information function while mitigating the harmful acoustic effect.
3Adaptability or versatility
If continuous DTMF tones are generated for remote access operations, then remote functionality is enabled, but dialing confirmation tones become excessively objectionable
Solution Approach 1:
The patent enables dynamic control of confirmation tone attenuation that works across different operational modes including continuous DTMF tone generation for remote access. When the enable signal is active, the attenuator continuously reduces the volume of confirmation tones even during extended key-holding operations, preventing the accumulation of annoyance over time while preserving the remote access functionality that requires continuous tone generation.
Data Source
AI summary
A method, system, and apparatus for attenuating a dialing confirmation tone includes receiving an enable signal from a tactile user input device, generating at least one dual-tone multiple frequency (DTMF) tone, and communicating the at least one DTMF tone to a telephone line. The method further includes attenuating a signal level of the at least one DTMF tone by a predetermined amount to produce at least one attenuated dialing confirmation tone in response to receiving the enable signal, and communicating the at least one attenuated dialing confirmation tone to an audio output device.