Method and apparatus for intelligent dual-tone multi-frequency (DTMF) decoding and identification

• US 10,264,333 B1
• Filed: 11/17/2017
• Issued: 04/16/2019
• Est. Priority Date: 11/17/2017
• Status: Active Grant

• Current Assignee: Steven Eric Presser
• Original Assignee: Steven Eric Presser
• Inventors: Presser, Steven Eric
• Primary Examiner(s): Teshale, Akelaw
• Application Number:
  US15/816,841
• Time in Patent Office: 515 Days
• Field of Search: 379 3201, 379 8801, 379386, 37911201, 37911206, 379133, 379135, 379 23, 379 2702, 37935501, 37935703
• CPC Class Codes: H04M 1/50 by generating or selecting currents of predetermined frequencies or combinations of frequencies
• CPC Class Codes: H04M 1/57 Arrangements for indicating or recording the number of the calling subscriber at the called subscriber's set at the operator set in a manual exchange H04M5/20
• CPC Class Codes: H04Q 1/45 using multi-frequency signalling H04Q1/46 takes precedence
• CPC Class Codes: H04Q 1/4575 which are transmitted in digital form
• CPC Class Codes: H04Q 1/46 comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current
• CPC Class Codes: H04Q 2213/13096 Digital apparatus individually associated with a subscriber line, digital line circuits

Abstract

A dual-tone multi-frequency (DTMF) decoder may decode DTMF symbols received in an audio input and transfer the symbols to a buffer. A volume accumulator may determine whether the audio input includes audio with volume above a predetermined threshold. The buffer may receive instructions from the timer or volume accumulator to transfer stored DTMF symbols to a filter, which may identify a characteristic of information conveyed by the DTMF symbols and send the identified characteristic information to an output device. The timer may determine a time associated with when each DTMF symbol was received and transfer each associated time to the buffer, which may transfer each associated time to a group boundary detector that may determine a predetermined number of longest time durations in between the DTMF symbols. The presence of a predetermined number of longest time durations in between the DTMF symbols may indicate a telephone number format.

Claims

1. An apparatus configured to identify a characteristic of information conveyed by dual-tone multi-frequency (DTMF) symbols, the apparatus comprising:

communication circuitry configured to receive an audio input;

a DTMF decoder coupled to the communication circuitry that is configured to decode DTMF symbols included in the audio input received from the communication circuitry and configured to transfer the decoded DTMF symbols to a buffer to be stored;

a timer coupled to the DTMF decoder and the buffer;

a volume accumulator coupled to the communication circuitry and the timer and configured to determine whether the audio input includes audio with volume above a predetermined threshold and configured to reset the timer when the audio input includes audio with volume above the predetermined threshold;

the buffer configured to receive an instruction from the timer or the volume accumulator to transfer each stored DTMF symbol to a filter; and

the filter configured to identify a characteristic of information conveyed by the DTMF symbols and further configured to send the identified characteristic information to an output device.

2. The apparatus of claim 1, wherein the filter is further configured to identify a characteristic of the information conveyed by the DTMF symbols by matching the DTMF symbols to a pattern.

3. The apparatus of claim 2, wherein the pattern is selected from the group consisting of a telephone number format and a telephone routing information format.

4. The apparatus of claim 1, wherein the timer is configured to determine a time associated with when each DTMF symbol was received in the audio input and configured to transfer each associated time to the buffer to be stored, and wherein the buffer is further configured to transfer each associated time to a group boundary detector that is configured to receive the DTMF symbols and associated time from the buffer and determine a predetermined number of longest time durations in between certain of the DTMF symbols.

5. The apparatus of claim 4, wherein the group boundary detector is further configured to identify groups of DTMF symbols where the time duration between symbols in a group is less than a time duration between groups of symbols.

6. The apparatus of claim 4, wherein the predetermined number of longest time durations in between certain of the DTMF symbols is determined by a longest difference between an observed time duration and an expected time duration.

7. The apparatus of claim 4, wherein the group boundary detector is further configured to determine whether the predetermined number of longest time durations indicate a domestic or international telephone number format.

8. The apparatus of claim 1, wherein the timer is further configured to expire after a predetermined duration of time indicating silence included in the audio input.

9. The apparatus of claim 1, wherein audio with volume above the predetermined threshold indicates voice included in the audio input.

10. The apparatus of claim 1, wherein the output device is an electronic device with a memory for storage.

11. A method for identifying a characteristic of information conveyed by dual-tone multi-frequency (DTMF) symbols, the method comprising:

receiving, by communication circuitry, an audio input;

decoding, by a DTMF decoder coupled to the communication circuitry, each DTMF symbol included in the audio input received from the communication circuitry;

transferring, by the DTMF decoder, the decoded DTMF symbols to a buffer to be stored;

determining, by a volume accumulator coupled to the communication circuitry and a timer, whether the audio input includes audio with volume above a predetermined threshold;

resetting, by the volume accumulator, the timer when the audio input includes audio with volume above the predetermined threshold;

transferring, by the buffer, each stored DTMF symbol to a filter when instructed by the timer or the volume accumulator;

identifying, by the filter, a characteristic of information conveyed by the DTMF symbols; and

sending, by the filter, the identified characteristic information to an output device.

12. The method of claim 11, wherein the identifying comprises matching the DTMF symbols to a pattern.

13. The method of claim 12, wherein the pattern is selected from the group consisting of a telephone number format and a telephone routing information format.

14. The method of claim 11, wherein the timer is configured to determine a time associated with when each DTMF symbol was received in the audio input and configured to transfer each associated time to the buffer to be stored, and wherein the buffer is further configured to transfer each associated time to a group boundary detector that is configured to receive the DTMF symbols and associated time from the buffer and determine a predetermined number of longest time durations in between certain of the DTMF symbols.

15. The method of claim 14, wherein the group boundary detector is further configured to identify groups of DTMF symbols where the time duration between symbols in a group is less than a time duration between groups of symbols.

16. The method of claim 14, wherein the predetermined number of longest time durations in between certain of the DTMF symbols is determined by a longest difference between an observed time duration and an expected time duration.

17. The method of claim 14, wherein the group boundary detector is further configured to determine whether the predetermined number of longest time durations indicate a domestic or international telephone number format.

18. An apparatus configured to identify a characteristic of information conveyed by dual-tone multi-frequency (DTMF) symbols, the apparatus comprising:

communication circuitry configured to receive an audio input;

a programmed processor coupled to memory and configured to execute instructions stored in the memory;

the programmed processor further configured to determine whether the audio input includes at least one DTMF symbol;

if the audio input includes at least one DTMF symbol, the programmed processor further configured to store in the memory the at least one DTMF symbol;

the programmed processor further configured to determine whether the audio input includes audio with volume above a predetermined threshold;

if the audio input does not include audio with volume above the predetermined threshold, the programmed processor further configured to determine whether a timer expired;

if the audio input includes audio with volume above the predetermined threshold or the timer expired, the programmed processor further configured to determine whether the stored at least one DTMF symbol indicates a format of a telephone number; and

if the stored at least one DTMF symbol indicates the format of a telephone number, the communication circuitry further configured to send the stored at least one DTMF symbol to an output device.

19. The apparatus of claim 18, wherein the programmed processor is further configured to store in the memory a time associated with when the at least one DTMF symbol was received in the audio input and to determine a predetermined number of longest time durations in between certain of the stored at least one DTMF symbol.

20. The apparatus of claim 19, wherein the programmed processor is further configured to identify groups of DTMF symbols where the time duration between symbols in a group is less than a time duration between groups of symbols.

21. An apparatus configured to identify a characteristic of information conveyed by dual-tone multi-frequency (DTMF) symbols, the apparatus comprising:

communication circuitry configured to receive an audio input;

a DTMF decoder coupled to the communication circuitry that is configured to decode DTMF symbols included in the audio input received from the communication circuitry and configured to transfer the decoded DTMF symbols to a buffer to be stored;

a timer coupled to the DTMF decoder and the buffer;

a voice activity detector coupled to the communication circuitry and the timer and configured to determine whether the audio input includes voice information and configured to reset the timer when the audio input includes voice information for longer than a predetermined length of time;

the buffer configured to receive an instruction from the timer or the voice detector to transfer each stored DTMF symbol to a filter; and

the filter configured to match the DTMF symbols to a pattern and further configured to send the matched DTMF symbols to an output device.