Machine answer detection

• US 5,371,787 A
• Filed: 03/01/1993
• Issued: 12/06/1994
• Est. Priority Date: 03/01/1993
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Dialogic, Inc. (Enghouse Systems Limited)
• Inventors: Hamilton, Chris A.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US08/024,409
• Time in Patent Office: 645 Days
• Field of Search: 379/386, 379/92, 379/88, 379/69, 379/97, 379/100, 379/216, 379/104, 375/104
• US Class Current: 379/386
• CPC Class Codes: H04M 1/654 Telephone line monitoring circuits therefor, e.g. ring detectors
• CPC Class Codes: H04M 1/82 Line monitoring circuits for call progress or status discrimination for detecting caller identity H04M1/573
• CPC Class Codes: H04M 2203/2027 Live party detection

Abstract

A detector to indicate if a telephone call was answered by an answering machine or a live person includes (to analyze frames): a click detector; a ring detector; a voice detector; an energy detector; and a controller. The controller routes to: a voice analyzer if voice occurred; a ring analyzer if ring started, continues, or ended; a noise detector if there is neither ring nor voice; a click analyzer if a click occurred; an answer analyzer if ring did not start in the frame; and a silence analyzer. The noise detector detects noise; the ring analyzer detects start time, end time, and length of ring; the click analyzer detects click time; the answer analyzer detects call answer time; the silence analyzer detects silence and the time of predetermined lengths of silence; and the voice analyzer detects the first frame of voice and routes to an on-first voice analyzer or to an after-first voice analyzer. Lastly, the on-first voice analyzer determines if the call was answered by an answering machine and routes to a reporter and the after-first voice analyzer determines if the telephone call was answered by an answering machine or a live person and routes to the reporter.

Claims

1. An answering machine detector for determining whether a telephone call has been answered by an answering machine or by a live person, the answering machine detector comprising:

means for detecting a first measure of a length of time between the time the telephone call is answered and the time of first voice response; and

means for generating a signal indicating that the telephone call was answered by the answering machine if the first measure of a length of time is greater than a predetermined time-to-answer length.

2. The answering machine detector of claim 1 which further comprises means for detecting a second measure of a length of time of the first voice response;

and

means for generating a signal indicating that the telephone call was answered by the answering machine if the second measure of a length of time exceeds an answer size time length.

3. The answering machine detector of claim 2 which further comprises means for adapting the answer size time length depending on the value of the first measure of a length of time.

4. The answering machine detector of claim 3 which further comprises means for determining a measure of a length of silence which occurs during the first voice response;

and

means for generating a signal indicating that the telephone call was answered by a live person if the measure of a length of silence exceeds a predetermined amount.

5. An answering machine detector for determining whether a telephone call has been answered by an answering machine or by a live person, the answering machine detector comprising:

means for detecting a first measure of a length of time between the time the telephone call is answered and the time of first voice response;

means for determining a measure of noise which occurs before the time of the first voice response; and

means for generating a signal indicating that the telephone call was answered by the answering machine if the measure of noise has first predetermined characteristics or if the measure of noise has second predetermined characteristics and the first measure of a length of time is greater than a predetermined time-to-answer time length.

6. A method for determining whether a telephone call has been answered by an answering machine or by a live person, the method comprising the steps of:

detecting the length of time between the time the telephone call is answered and the time of first voice response;

generating a signal indicating that the telephone call was answered by the answering machine if the length of time is greater than a predetermined answer time length;

detecting the length of time of the first voice response; and

generating a signal indicating that the telephone call was answered by the answering machine if the length of time of the first voice response exceeds an adaptive answer size time length.

7. An answering machine detector for determining whether a telephone call has been answered by an answering machine or by a live person, the answering machine detector comprising:

a click detector means, responsive to a telephone signal generated during a telephone call, for detecting a click in a predetermined period of time referred to as a frame and for storing a click indication thereof in a storage means;

a ring detector means, responsive to the telephone signal, for detecting whether a ring event started, continues, or ended in the frame and for storing a ring indication thereof in the storage means;

a voice detector means, responsive to the telephone signal, for detecting whether a voice event occurred in the frame and for storing a voice indication thereof in the storage means;

an energy detector means, responsive to the telephone signal, for;

(a) determining a measure of the total energy of the telephone signal in the frame and a measure of energy concentration of the signal referred to as broad;

(b) storing the measures in the storage means; and

(c) transmitting a signal to a controller means;

wherein the controller means is apparatus, responsive to the signal from the energy detector means, for;

(a) obtaining the voice indication from the storage means and, if a voice event occurred, transmitting a signal to a voice analyzer means;

(b) obtaining the ring indication from the storage means and, if a ring event started, continues, or ended in the frame, transmitting a signal to a ring analyzer means;

(c) if the frame is not inside a ring event or a voice event, transmitting a signal to a noise detector means;

(d) obtaining the click indication from the storage means and, if a click occurred in the frame, transmitting a signal to a click analyzer means;

(e) if the ring indication does not indicate that a ring event started in the frame, transmitting a signal to an answer analyzer means; and

(f) transmitting a signal to a silence analyzer means;

wherein;

the noise detector means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting whether the telephone signal during the frame is noise and, if so, for storing noise information in the storage means;

the ring analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for storing an indication of the length of a ring event in the storage means;

the click analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for storing an indication of the time a click was detected in the storage means;

the answer analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting an indication of the time at which the telephone call is answered and for storing the indication of the time in the storage means;

the silence analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting silence, for determining an indication of the time at which a predetermined time length of silence occurred, and for storing the indication of the time in the storage means; and

the voice analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for determining whether the frame is the first frame in which a voice event has occurred and, if so, for transmitting a signal to an on-first voice analyzer means and, if not, for transmitting a signal to an after-first voice analyzer means;

wherein;

the on-first voice analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting whether the telephone call was answered by an answering machine and, if so, for transmitting a signal to a reporter means; and

the after-first voice analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for determining whether the telephone call was answered by an answering machine or a live person and for transmitting a signal indicative thereof to the reporter means;

wherein the reporter means comprises means, responsive to signals from the on-first voice analyzer means and the after-first voice analyzer means, for generating a signal indicating whether the telephone call was answered by an answering machine or by a live person.

8. The answering machine detector of claim 7 wherein the answer analyzer means for detecting the indication of the time at which the telephone call is answered comprises means for the detecting the frame at which the measure of total energy is above a predetermined answer threshold after a ring-off event.

9. The answering machine detector of claim 7 wherein the silence analyzer means comprises means for detecting a frame at which the measure of total energy is below a predetermined silence threshold and means for counting such consecutive frames.

10. The answering machine detector of claim 7 wherein the noise detector means comprises means for detecting that the telephone signal is noise by determining:

(a) whether the measure of total energy is less than a first predetermined threshold or (b) whether the measure of total energy is greater than a second predetermined threshold or broad is greater than a predetermined broad threshold.

11. The answering machine detector of claim 7 wherein the ring analyzer means comprises means for detecting the time at which a ring-on event occurred and the time at which a ring-off event occurred and for determining the indication of the length of a ring event from the difference thereof.

12. The answering machine detector of claim 7 wherein the on-first voice analyzer means comprises means for detecting the length of time between the time the telephone call is answered and the time of first voice response and for transmitting the signal to the reporter means indicating that the telephone call was answered by the answering machine if the length of time is greater than a predetermined answer time length.

13. The answering machine detector of claim 12 wherein the after-first voice analyzer means comprises means for detecting the length of time of the first voice response and for transmitting the signal to the reporter means indicating that the telephone call was answered by the answering machine if the length of time of the first voice response exceeds an adaptive answer size time length.

14. A method for determining whether a telephone call has been answered by an answering machine or by a live person, the method comprising the steps of:

responsive to a telephone signal generated during a telephone call;

(a) detecting a click in a predetermined period of time referred to as a frame and storing a click indication thereof;

(b) detecting whether a ring event started, continues, or ended in the frame and storing a ring indication thereof;

(c) detecting whether a voice event occurred in the frame and storing a voice indication thereof;

(d) (i) determining a measure of the total energy of the telephone signal in the frame and a measure of energy concentration of the signal referred to as broad and (ii) storing the measures;

responsive to the end of a frame;

(a) obtaining the voice indication and, if a voice event occurred, transferring to a voice analyzing step;

(b) obtaining the ring indication and, if a ring event started, continues, or ended in the frame, transferring to a ring analyzing step;

(c) if the frame is not inside a ring event or a voice event, transferring to a noise detecting step;

(d) obtaining the click indication from the storage means and, if a click occurred in the frame, transferring to a click analyzing step;

(e) if the ring indication does not indicate that a ring event started in the frame, transferring to an answer analyzing step; and

(f) transferring to a silence analyzing step;

wherein;

the noise detecting step comprises the steps of, responsive to stored information, detecting whether the telephone signal during the frame is noise and, if so, storing noise information;

the ring analyzing step comprises the steps of, responsive to stored information, storing an indication of the length of a ring event;

the click analyzing step comprises the steps of, responsive to stored information, storing an indication of the time a click was detected;

the answer analyzing step comprises the steps of, responsive to stored information, detecting an indication of the time at which the telephone call is answered and storing the indication of the time;

the silence analyzing step comprises the steps of, responsive to stored information, detecting silence, determining an indication of the time at which a predetermined time length of silence occurred, and storing the indication of the time; and

the voice analyzing step comprises the steps of, responsive to stored information, determining whether the frame is the first frame in which a voice event has occurred and, if so, transferring to an on-first voice analyzing step and, if not, transferring to an after-first voice analyzing step;

wherein;

the on-first voice analyzing step comprises the steps of, responsive to stored information, detecting whether the telephone call was answered by an answering machine and, if so, for transferring an indication thereof to a reporting step; and

the after-first voice analyzing step comprises the steps of, responsive to stored information, determining whether the telephone call was answered by an answering machine or a live person and for transferring an indication thereof to the reporting step;

wherein the reporting step comprises the steps of, responsive to indications from the on-first voice analyzing step and the after-first voice analyzing step, generating a signal indicating whether the telephone call has been answered by an answering machine or by a live person.

15. An answering machine detector for determining whether a telephone call has been answered by an answering machine or by a live person, the answering machine detector comprising:

a ring detector means, responsive to the telephone signal, for detecting whether a ring event started, continues, or ended in a predetermined period of time referred to as a frame and for storing a ring indication thereof in the storage means;

a voice detector means, responsive to the telephone signal, for detecting whether a voice event occurred in the frame and for storing a voice indication thereof in the storage means;

an energy detector means, responsive to the telephone signal, for;

(a) determining a measure of the total energy of the telephone signal in the frame and a measure of energy concentration of the signal referred to as broad;

(b) storing the measures in the storage means; and

(c) transmitting a signal to a controller means;

wherein the controller means is apparatus, responsive to the signal from the energy detector means, for;

(a) obtaining the voice indication from the storage means and, if a voice event occurred, transmitting a signal to a voice analyzer means;

(b) obtaining the ring indication from the storage means and, if a ring event started, continues, or ended in the frame, transmitting a signal to a ring analyzer means;

(c) if the frame is not inside a ring event or a voice event, transmitting a signal to a noise detector means;

(d) if the ring indication does not indicate that a ring event started in the frame, transmitting a signal to an answer analyzer means; and

(e) transmitting a signal to a silence analyzer means;

wherein;

the noise detector means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting whether the telephone signal during the frame is noise and, if so, for storing noise information in the storage means;

the ring analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for storing an indication of the length of a ring event in the storage means;

the answer analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting an indication of the time at which the telephone call is answered and for storing the indication of the time in the storage means;

the silence analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting silence, for determining an indication of the time at which a predetermined time length of silence occurred, and for storing the indication of the time in the storage means; and

the voice analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for determining whether the frame is the first frame in which a voice event has occurred and, if so, for transmitting a signal to an on-first voice analyzer means and, if not, for transmitting a signal to an after-first voice analyzer means;

wherein;

the on-first voice analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for detecting whether the telephone call was answered by an answering machine and, if so, for transmitting a signal to a reporter means; and

the after-first voice analyzer means comprises means, responsive to the signal from the controller means and information obtained from the storage means, for determining whether the telephone call was answered by an answering machine or a live person and for transmitting a signal indicative thereof to the reporter means;

wherein the reporter means comprises means, responsive to signals from the on-first voice analyzer means and the after-first voice analyzer means, for generating a signal indicating whether the telephone call was answered by an answering machine or by a live person.