DTMF circuit and method of relaying DTMF digits in a DTMF circuit

Patent metadata

Field	Value
Publication number	US-9094497-B1
Application number	US-201313947461-A
Country	US
Kind code	B1
Filing date	Jul 22, 2013
Priority date	Jul 22, 2013
Publication date	Jul 28, 2015
Grant date	Jul 28, 2015

Abstract

A Dual Tone Multi Frequency (DTMF) circuit for relaying DTMF digits includes a communication interface, a storage system configured to store a sampling window size, a DTMF test sequence, a returned DTMF sequence, and one or more DTMF digits, with the one or more DTMF digits to be transferred to a second DTMF circuit by the DTMF circuit, and a processing system. The processing system receives the one or more DTMF digits via the communication interface and an input sampling window, generates the DTMF test sequence and transmits the DTMF test sequence to the second DTMF circuit, compares the DTMF test sequence to a returned DTMF sequence received back from the second DTMF circuit, and if the returned DTMF sequence is not the same as the DTMF test sequence, adjusts the sampling window size of the input sampling window.

First claim

What is claimed is:

1. A first Dual Tone Multi Frequency (DTMF) circuit for relaying DTMF digits, the first DTMF circuit comprising:
a communication interface adapted to exchange one or more DTMF digits over a communication link;
a storage system configured to store a sampling window size, a DTMF test sequence, a returned DTMF sequence, and the one or more DTMF digits, with the one or more DTMF digits to be transferred to a second DTMF circuit by the first DTMF circuit; and
a processing system coupled to the communication interface and the storage system, with the processing system configured to receive the one or more DTMF digits via the communication interface and an input sampling window, generate the DTMF test sequence and transmit the DTMF test sequence as DTMF tones to the second DTMF circuit, compare the DTMF test sequence to a returned DTMF sequence received as DTMF tones within the input sampling window back from the second DTMF circuit, and if the returned DTMF sequence includes a different number of DTMF digits than the DTMF test sequence, then adjust the sampling window size of the input sampling window.

2. The first DTMF circuit of claim 1 , wherein the sampling window size may be lengthened or shortened by the first DTMF circuit.

3. The first DTMF circuit of claim 1 , wherein the DTMF test sequence comprises one or more pulses of a predetermined pulse width and/or a predetermined duty cycle.

4. The first DTMF circuit of claim 1 , wherein the generating, comparing, and adjusting steps are iteratively performed until the returned DTMF sequence is the same as the DTMF test sequence.

5. The first DTMF circuit of claim 1 , further comprising transferring the one or more DTMF digits to the second DTMF circuit after the sampling window size has been adjusted.

6. The first DTMF circuit of claim 1 , wherein the processing system requests re-receipt the one or more DTMF digits after the sampling window size has been adjusted.

7. A method of relaying Dual Tone Multi Frequency (DTMF) digits in a first DTMF circuit, comprising:
the first DTMF circuit receiving one or more DTMF digits via an input sampling window, with the one or more DTMF digits to be transferred to a second DTMF circuit by the first DTMF circuit;
the first DTMF circuit generating a DTMF test sequence and transmitting the DTMF test sequence as DTMF tones to the second DTMF circuit;
the first DTMF circuit comparing the DTMF test sequence to a returned DTMF sequence received as DTMF tones within the input sampling window back from the second DTMF circuit; and
if the returned DTMF sequence includes a different number of DTMF digits than the DTMF test sequence, then the first DTMF circuit adjusting a sampling window size of the input sampling window.

8. The method of claim 7 , wherein the sampling window size may be lengthened or shortened by the first DTMF circuit.

9. The method of claim 7 , wherein the DTMF test sequence comprises one or more pulses of a predetermined pulse width and/or a predetermined duty cycle.

10. The method of claim 7 , wherein the generating, comparing, and adjusting steps are iteratively performed until the returned DTMF sequence is the same as the DTMF test sequence.

11. The method of claim 7 , further comprising transferring the one or more DTMF digits to the second DTMF circuit after the sampling window size has been adjusted.

12. The method of claim 7 , wherein the first DTMF circuit requests re-receipt of the one or more DTMF digits after the sampling window size has been adjusted.

13. A method of relaying Dual Tone Multi Frequency (DTMF) digits in a first DTMF circuit, comprising:
the first DTMF circuit receiving one or more DTMF digits via an input sampling window, with the one or more DTMF digits to be transferred to a second DTMF circuit by the first DTMF circuit;
the first DTMF circuit generating a DTMF test sequence and transmitting the DTMF test sequence as DTMF tones to the second DTMF circuit;
the first DTMF circuit determining if an elapsed time has exceeded a predetermined time threshold;
if the elapsed time has not exceeded the predetermined time threshold, then the first DTMF circuit comparing the DTMF test sequence to a returned DTMF sequence received as DTMF tones within the input sampling window back from the second DTMF circuit; and
if the returned DTMF sequence includes a different number of DTMF digits than the DTMF test sequence, then the first DTMF circuit adjusting a sampling window size of the input sampling window and iteratively repeating the generating, determining, and comparing steps.

14. The method of claim 13 , wherein the sampling window size may be lengthened or shortened by the first DTMF circuit.

15. The method of claim 13 , wherein the DTMF test sequence comprises one or more pulses of a predetermined pulse width and/or a predetermined duty cycle.

16. The method of claim 13 , further comprising transferring the one or more DTMF digits to the second DTMF circuit after the sampling window size has been adjusted.

17. The method of claim 13 , wherein the first DTMF circuit requests re-receipt of the one or more DTMF digits after the sampling window size has been adjusted.

Assignees

• Sprint Communications Co

Inventors

• Geis Robert E
• Oroskar Siddharth
• Gorman Pierce Andrew
• Young Gerald Baylis Prince

Classifications

• H04Q1/45

  using multi-frequency signalling (H04Q1/46 takes precedence) · CPC title

• H04M7/1295 Primary

  Details of dual tone multiple frequency signalling · CPC title

• H04Q1/457 Primary

  with conversion of multifrequency signals into digital signals · CPC title