Call-waiting tone detection technique

• US 6,496,572 B1
• Filed: 12/20/2001
• Issued: 12/17/2002
• Est. Priority Date: 05/26/1998
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: AltoCom, Inc. (Broadcom, Inc.)
• Inventors: Draganic, Zarko, Liang, Haixiang
• Primary Examiner(s): WOO, STELLA L
• Application Number:
  US10/029,017
• Time in Patent Office: 362 Days
• Field of Search: 379/93.35, 379/215.01, 379/406.01, 379/406.02, 379/93.09, 379/93.11, 379/93.17, 379/93.23, 379/93.28, 379/93.31, 375/222
• US Class Current: 379/93.35
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 3/4281 when the called subscriber is connected to a data network using his telephone line, e.g. dial-up connection, Internet browsing

Abstract

Reliable detection of a call-waiting tone is provided by employing a correlation based technique. A modem or other device employing such a technique need not rely on carrier drop detection and is generally insensitive to other energy or noise on the line.

Claims

1. A communications device comprising:

a telephone-line communications interface;

a call-waiting tone detector coupled to the telephone-line communications interface, the call-waiting tone detector correlating a received signal with a phase-shifted version thereof to identify call-waiting tone therein, wherein the phase-shift corresponds to a period of the call-waiting tone.

2. The communications device of claim 1,

wherein the phase-shift substantially corresponds to an integer multiple of the period of the call-waiting tone.

3. The communications device of claim 1,

wherein the phase-shift substantially corresponds to a half multiple of the period of the call-waiting tone.

4. The communications device of claim 1, embodied as a modem.

5. The communications device of claim 1, embodied as one or more of:

a set top box;

an internet terminal device;

a satellite or pay TV authorization device;

a fax machine;

a personal digital assistant;

a portable computer; and

a cellular or mobile phone.

6. The communications device of claim 1, embodied as a telephone, speakerphone or other voice terminal equipment.

7. The communications device of claim 1, providing an internet call-waiting facility while operating in accordance with ITU-T Recommendation V.34.

8. The communications device of claim 1, providing an internet call-waiting facility.

9. The communications device of claim 1, providing a modem on hold facility.

10. A method of detecting a call-waiting tone, the method comprising:

correlating a received signal with two phase shifted versions thereof, wherein phase shifts for respective ones of the correlations substantially correspond to an integer multiple and to a half-multiple of a period of the call-waiting tone, respectively; and

evaluating the results of the correlations against respective thresholds to identify the call-waiting tone.

11. A call-waiting detector comprising:

a telephone-line communications interface; and

a tone detector coupled to the telephone-line communications interface, the tone detector correlating a received signal with a phase-shifted version thereof to identify call-waiting tone therein, wherein the phase-shift corresponds to a period of the call-waiting tone.

12. The call-waiting detector of claim 11,

wherein the phase-shift substantially corresponds to an integer multiple of the period of the call-waiting tone.

13. The call-waiting detector of claim 11,

wherein the phase-shift substantially corresponds to a half multiple of the period of the call-waiting tone.

14. The call-waiting detector of claim 11, integrated into a receive path of a modem.

15. The call-waiting detector of claim 11, integrated into a receive path of:

a set top box;

an internet terminal device;

a satellite or pay TV authorization device;

a fax machine;

a personal digital assistant;

a portable computer; and

a cellular or mobile phone.

16. The call-waiting detector of claim 11, embodied in a telephone, speakerphone or other voice terminal equipment.

17. The call-waiting detector of claim 11, coupled between

a telephone line and

a modem.

18. The call-waiting detector of claim 17, further coupled between the telephone line and a telephone handset.

19. The call-waiting detector of claim 11, coupled between

a telephone line and

a telephone handset.

20. The call-waiting detector of claim 11, further comprising:

an incoming call indication interface to an on-screen visual display.

21. The call-waiting detector of claim 11, further comprising:

an incoming call indication interface that supplies a ring indication for supply to a telephone handset.

22. The call-waiting detector of claim 11, wherein the call waiting tone is a 440 Hz tone.

23. A method of operating a communications device, the method comprising:

initiating a session with a remote data communications device;

receiving a signal via a telephone line, the signal including data from the remote data communications device;

detecting in the received signal a call-waiting tone and, in response thereto, indicating an incoming call, wherein the detection includes correlating the received signal with a phase-shifted version thereof to identify the call-waiting tone, wherein the phase-shift corresponds to a period of the call-waiting tone; and

in response to acceptance of the incoming call, supplying a flash indication on the telephone line; and

suspending the session.

24. The method of claim 23,

wherein the phase-shift substantially corresponds to an integer multiple of the period of the call-waiting tone.

25. The method of claim 23,

wherein the phase-shift substantially corresponds to a half multiple of the period of the call-waiting tone.

26. The method of claim 23,

wherein the acceptance is by a user.

27. The method of claim 23,

wherein the detection occurs while the communications device is in a doze state.

28. The method of claim 23, further comprising:

resuming the session.

29. The method of claim 23, further comprising:

supplying the incoming call indication visually.

30. The method of claim 23, further comprising:

supplying the incoming call indication audibly.

31. The method of claim 23, wherein the communications device is a modem.

32. The method of claim 23, wherein the communications device is embodied as one or more of:

a set top box;

an internet terminal device;

a satellite or pay TV authorization device;

a fax machine;

a personal digital assistant;

a portable computer; and

a cellular or mobile phone.

33. The method of claim 23, wherein the communications device is a telephone, speakerphone or other voice terminal equipment.

34. A method of operating a communications device, the method comprising:

initiating a session with a remote data communications device;

receiving a signal including data from the remote data communications device;

detecting in the received signal a call-waiting tone and, in response thereto, indicating an incoming call, wherein the detection includes correlating the received signal with a phase-shifted version thereof to identify the call-waiting tone, wherein the phase-shift corresponds to a period of the call-waiting tone; and

continuing the session if the incoming call is rejected or ignored.

35. The method of claim 34,

wherein the phase-shift substantially corresponds to an integer multiple of the period of the call-waiting tone.

36. The method of claim 34,

wherein the phase-shift substantially corresponds to a half multiple of the period of the call-waiting tone.

37. The method of claim 34,

wherein the rejection is by a user.

38. The method of claim 34, further comprising:

reestablishing a connection between the communications device and the remote data communications device.

39. The method of claim 34, further comprising:

supplying the incoming call indication visually.

40. The method of claim 34, further comprising:

supplying the incoming call indication audibly.

41. The method of claim 34, wherein the communications device is a modem.

42. The method of claim 34, wherein the communications device is embodied as or in one or more of:

a set top box;

an internet terminal device;

a satellite or pay TV authorization device;

a fax machine;

a personal digital assistant;

a portable computer; and

a cellular or mobile phone.

43. An apparatus comprising:

a receive communications path that includes at least near-end echo cancellation; and

a call-waiting tone detector coupled into the receive communications path to correlate phase-shifted representations of an echo cancelled received signal and thereby detect presence 440 Hz tone therein.

44. The apparatus of claim 43,

wherein at least one phase-shift corresponds a number of samples that substantially corresponds to an integer multiple of the period of the 440 Hz tone.

45. The apparatus of claim 43,

wherein at least one phase-shift corresponds a number of samples that substantially corresponds to an half multiple of the period of the 440 Hz tone.

46. The apparatus of claim 43, embodied as a communications device and further comprising:

a processor,

wherein both the receive communications path and the call waiting tone detector are embodied as software executable by the processor.

47. The communications device of claim 46, further comprising:

user interface software also executable by the processor.

48. The communications device of claim 47,

wherein the user interface software is responsive to an indication from the call waiting tone detector and in response thereto supplies a visual or audible incoming call indication.

49. The communications device of claim 46, configured as one or more of:

a personal digital assistant;

a portable computer; and

a cellular or mobile phone.

50. The apparatus of claim 43, embodied as a speakerphone or other voice terminal equipment.

51. The apparatus of claim 43, at least partially embodied as a computer program product encoding instructions in a computer readable medium selected from the set of media including magnetic storage media, optical storage media and communications media conveying signals.

52. An apparatus comprising:

means for receiving a signal from a telephone line; and

means for correlating the received signal with a phase-shifted version thereof to identify call-waiting tone therein, wherein the phase-shift corresponds to a period of the call-waiting tone.

53. The apparatus of claim 52,

means for correlating the received signal with at least a second phase-shifted version thereof, wherein the phase-shift and the second phase-shift respectively correspond to an integer multiple and a half multiple of the period of the call-waiting tone.

54. The apparatus of claim 52,

wherein the phase-shift substantially corresponds to an integer multiple of the period of the call-waiting tone.

55. The apparatus of claim 52,

wherein the phase-shift substantially corresponds to a half multiple of the period of the call-waiting tone.