Patents Assigned to Dialogic Corporation
  • Patent number: 5604793
    Abstract: A tone blocking system for use preferably in conferencing systems in order to prevent control tones from being transmitted to other conferees is disclosed. The buffer length used to process the signal and detect tones is varied, being increased when a tone is suspected to allow for sophisticated tone detection algorithms, and being decreased when silence is present by trimming the silence away. The technique minimizes delay, and its degrading effect on echo, but nonetheless provides for a lengthy buffer required to do reliable tone detection. The invention is applicable to any signal other than tone as well.
    Type: Grant
    Filed: August 3, 1995
    Date of Patent: February 18, 1997
    Assignee: Dialogic Corporation
    Inventors: Prabhakar Chitrapu, Wei Lin
  • Patent number: 5459781
    Abstract: A technique for improved DTMF detection utilizes a speech detector, either alone or in combination with other information from a voice processing arrangement, to adjust the sensitivity of the DTMF detector. The DTMF detector is turned completely off when the voice processing application is in the record mode, and when speech is detected.
    Type: Grant
    Filed: January 12, 1994
    Date of Patent: October 17, 1995
    Assignee: Dialogic Corporation
    Inventors: Jeffrey I. Kaplan, Nicholas Zwick
  • Patent number: 5450484
    Abstract: Voice detector for detecting whether a telephone signal has been produced by a voice. The voice detector obtains, on a per frame basis, measures of the following quantities relating to the telephone signal: total energy; energy and frequency of two largest energy peaks in a frequency spectrum; and signal-to-noise ratio (SNR). If the measure of total energy exceeds a predetermined threshold, the voice detector increments running sums of the following measures: total energy; frequency of the largest peak in the frequency spectrum; and SNR. Until a predetermined number of frames, referred to as a window, has been reached, for each frame, the voice detector determines whether the telephone signal was produced by ringing (incrementing a ring count if it was) and whether there is a local energy maximum (incrementing a local energy maximum count if there was).
    Type: Grant
    Filed: March 1, 1993
    Date of Patent: September 12, 1995
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 5450485
    Abstract: Apparatus for detecting whether a telephone call has been disconnected, which apparatus includes: (a) a click detector for detecting a click and for generating a "click indication"; (b) a telephone handset impact detector for detecting a telephone handset impact and for generating a "handset impact indication"; (c) a silence detector for detecting silence and for storing a "silent indication"; (d) a timer for determining a predetermined time interval and for transmitting a signal to a controller whenever the time period expires; wherein, in response to the signal, the controller analyzes the "click indication", the handset impact indication", and the "silent indication" to determine whether a predetermined sequence of handset impact, clicks, and silence was detected and, if so, for generating a signal indicating that the telephone call has been disconnected.
    Type: Grant
    Filed: April 19, 1994
    Date of Patent: September 12, 1995
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 5442694
    Abstract: A technique for software ring tone detection is disclosed utilizing, in the preferred embodiment, a recursive algorithm. The technique provides flexibility in that a digital signal processor may be reprogrammed to detect ring tone frequencies and amplitudes present in numerous different countries.
    Type: Grant
    Filed: April 12, 1994
    Date of Patent: August 15, 1995
    Assignee: Dialogic Corporation
    Inventors: Prabhakar Chitrapu, Zhibing Pan, Chet Juall, Andrew Dumont
  • Patent number: 5428662
    Abstract: Method and apparatus for detecting make-break clicks on a telephone line, i.e., clicks produced by going on-hook or off-hook. A click is detected by analyzing time slices of a telephone signal to detect a sharp positive transition in signal energy followed by a diminishing envelope of short duration. Three signal measures are utilized to determine whether a click has occurred: (a) a magnitude transition, i.e., a change of the magnitude of the amplitude of the signal over a short period of time; (b) a peak magnitude, i.e., a magnitude of the amplitude of the signal corresponding to the first acceptably large magnitude transition (the beginning of the click); and (c) a duration of the signal envelope. In accordance with the present invention: (a) the minimum allowable peak magnitude of a valid click is scaled to the maximum magnitude encountered as the telephone signal is analyzed, i.e.
    Type: Grant
    Filed: March 1, 1993
    Date of Patent: June 27, 1995
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 5404400
    Abstract: An embodiment of the present invention is an apparatus for placing a telephone call over a telephone line and for detecting whether the telephone call was answered by a live person, an answering machine, a facsimile machine, or a data apparatus such as a modem and, depending on the manner in which the telephone call was answered, for connecting: (a) either a human agent or a telephone dialogue application to the telephone line to speak to a live person; (b) a voice message delivery system to the telephone line to send a voice message to an answering machine; (c) a facsimile message delivery system to the telephone line to send a facsimile message to the facsimile machine; and (d) a data message delivery system to the telephone line to send a data message to the data machine.
    Type: Grant
    Filed: March 1, 1993
    Date of Patent: April 4, 1995
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 5371787
    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.
    Type: Grant
    Filed: March 1, 1993
    Date of Patent: December 6, 1994
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 5218636
    Abstract: Method and apparatus for detecting and identifying dial pulse digits in a telephone signal. An embodiment of the inventive method includes the steps of: detecting a dial pulse "0" digit; analyzing the dial pulse "0" digit to determine a predetermined set of data to provide a template which is characteristic of the dial pulse "0" digit; detecting a further dial pulse digit; analyzing the further dial pulse digit to determine a predetermined set of data which is characteristic of the further dial pulse digit; and comparing the predetermined set of data of the further dial pulse digit with the template to identify the further dial pulse digit.
    Type: Grant
    Filed: March 7, 1991
    Date of Patent: June 8, 1993
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 5212688
    Abstract: TDM bus and, in particular, a PCM Expansion Bus (PEB): (a) which permits a multiplicity of apparatus to monitor a TDM signal simultaneously and (b) wherein various timing and control signals are provided in a manner that minimizes the hardware needed by the apparatus for identifying, i.e., decoding, various channels in the TDM signal for accessing and inserting information therein.
    Type: Grant
    Filed: July 18, 1990
    Date of Patent: May 18, 1993
    Assignee: Dialogic Corporation
    Inventors: Jay L. Gerbehy, Richard P. Graber, Chester Juall
  • Patent number: 5185786
    Abstract: Method and apparatus for recovering in-bound calls to a call center, which in-bound calls were directed to overflow. An embodiment of the inventive method includes the steps of: logging telephone numbers of in-bound calls that overflow the handling capacity of the call center, which telephone numbers are provided by the signaling capacity of the network to the call center; determining when call center agents become available; automatically initiating calls back to the logged telephone numbers; detecting when calls are answered; and causing call center agents to be connected thereto.
    Type: Grant
    Filed: November 13, 1990
    Date of Patent: February 9, 1993
    Assignee: Dialogic Corporation
    Inventor: Nicholas Zwick
  • Patent number: 5161181
    Abstract: ANI Blocking System (ABS) logically interfaces between a calling party and a called party in a telephone network which provides CallerID and CallerID blocking. The ABS automatically: (1) accepts a call from the calling party; (2) places a call to the called party; and (3) connects the called party with the calling party.
    Type: Grant
    Filed: January 10, 1990
    Date of Patent: November 3, 1992
    Assignee: Dialogic Corporation
    Inventor: Nicholas Zwick
  • Patent number: 5046088
    Abstract: An ANI Converter System (ACS): (1) logically interfaces between: (a) a telephone network, on the one hand, and customer premises equipment (CPE), on the other hand, or (b) two portions of a switched telephone network, such as two tandem toll switching machines; (2) accepts incoming calls; (3) extracts in-band network routing and/or origination information such as ANI information; (4) uses the information to extract relevant information from a data base; and (5) places a call to a predetermined called party at, for example, a predetermined workstation to aid operators using the workstation in carrying out transactions with a calling party.
    Type: Grant
    Filed: October 31, 1989
    Date of Patent: September 3, 1991
    Assignee: Dialogic Corporation
    Inventor: Edwin K. Margulies
  • Patent number: 4979214
    Abstract: Method and apparatus for identifying telephone signals which are produced by a human voice. The method includes determining a measure of the energy of predetermined frequency bins of the frequency spectrum of the signal for a frame comprised of a predetermined number of consecutive samples of the signal, if the signal is an analog signal; averaging the measure of the energy of the predetermined frequency bins over a predetermined number of frames to provide a frame group average energy measure; determining the sum of the absolute value of the difference between the frame group average energy measure for all pairs of frame groups which are consecutive in time; and comparing the sum with a predetermined amount to identify the signal as having been produced by a human voice if the sum exceeds the predetermined amount.
    Type: Grant
    Filed: May 15, 1989
    Date of Patent: December 18, 1990
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 4932062
    Abstract: For faster realtime analysis related to Discrete Fourier Transform (DFT), prestored pre-multiplied values of amplitude times cosine and sine functions are used. Method and apparatus for determining the content of a predetermined frequency bin f in the frequency spectrum of a signal and, in particular, a signal which occurs in a telephone network, includes the step of storing on a storage means:C.sub.k (x.sub.k,n)=x.sub.k *cos(2.pi.kn/N) and S.sub.k (x.sub.k,n)=x.sub.k *sin(2.pi.kn/N)for: k=0, . . . , (N-1); n=0, . . . , (n-1); and x.sub.k ranging over all the values of the set of M predetermined digital levels into which the amplitude of the signal is mapped, if the signal is a digital signal, or into which a sample of the amplitude of the signal is mapped, if the signal is an analog signal. N is a predetermined number of amplitudes or samples of the amplitude of the signal which are used in analyzing the frequency spectrum and n is a frequency index.
    Type: Grant
    Filed: May 15, 1989
    Date of Patent: June 5, 1990
    Assignee: Dialogic Corporation
    Inventor: Chris A. Hamilton
  • Patent number: 4862492
    Abstract: Apparatus and method for measuring the transmission quality of a telephone line, for example, a telephone line connected between two voice processing systems. The apparatus includes means for generating a predetermined sequence of DTMF pulses having predetermined amplitude values and for transmitting them over a telephone line; means for receiving DTMF pulses from a telephone line and determining the value of each pulse; means for counting the number of received DTMF pulses; and means for comparing the number with a predetermined threshold value, whereby the telephone line is determined to have acceptable transmission quality if the number exceeds the predetermined threshold value. Further, in a preferred embodiment, the predetermined sequence of DTMF pulses comprises four groups of ten (10) DTMF pulses, each of which groups has succeedingly lower amplitude.
    Type: Grant
    Filed: October 26, 1988
    Date of Patent: August 29, 1989
    Assignee: Dialogic Corporation
    Inventor: Nicholas Zwick
  • Patent number: 4852149
    Abstract: A Call Filter System (CFS): (1) logically interfaces between a public telephone network and business customer premises equipment; (2) automatically processes incoming and outgoing calls which are amenable to such intervention; and (3) enlists the aid of human intervention on calls requiring such intervention.
    Type: Grant
    Filed: June 29, 1988
    Date of Patent: July 25, 1989
    Assignee: Dialogic Corporation
    Inventors: Nicholas Zwick, Charles R. Walden Jr., Louis J. Francz, Jay L. Gerbehy
  • Patent number: 4849688
    Abstract: Apparatus for detecting a single-frequency signal having a predetermined frequency in an analog signal includes means for converting the analog signal to a differentially encoded digital signal and detection means for detecting a single-frequency signal having the predetermined frequency from the differentially encoded digital signal. In a preferred embodiment, the detection means includes: means for detecting one cycle of the analog signal by detecting a signal maximum followed by detecting a signal minimum which is followed, in turn, by detecting another signal maximum; means for determining the length of the cycle, for determining whether the length is within predetermined bounds, and for keeping a count of such occurrences; and means for determining whether the count has reached a predetermined amount, whereby a single-frequency signal having the predetermined frequency has been detected.
    Type: Grant
    Filed: September 16, 1988
    Date of Patent: July 18, 1989
    Assignee: Dialogic Corporation
    Inventors: Christian J. Chuba, Charles R. Walden, Jr., Joseph J. Grecco, Jeffrey I. Feinstein
  • Patent number: 4760516
    Abstract: Circuitry which permits a plurality of peripherals to share a single interrupt signal line in computer systems and thereby increase the number of peripherals which can be supported.
    Type: Grant
    Filed: November 25, 1986
    Date of Patent: July 26, 1988
    Assignee: Dialogic Corporation
    Inventor: Nicholas Zwick