EP1121786A1 - Identification de dtmf rapide - Google Patents

Identification de dtmf rapide

Info

Publication number
EP1121786A1
EP1121786A1 EP99941106A EP99941106A EP1121786A1 EP 1121786 A1 EP1121786 A1 EP 1121786A1 EP 99941106 A EP99941106 A EP 99941106A EP 99941106 A EP99941106 A EP 99941106A EP 1121786 A1 EP1121786 A1 EP 1121786A1
Authority
EP
European Patent Office
Prior art keywords
signal
tone
transmission
tones
voice
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP99941106A
Other languages
German (de)
English (en)
Other versions
EP1121786A4 (fr
Inventor
Edward Morgan
Zoran Mladenovic
Piyush Patel
Qin Su
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telogy Networks Inc
Original Assignee
Telogy Networks Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telogy Networks Inc filed Critical Telogy Networks Inc
Publication of EP1121786A1 publication Critical patent/EP1121786A1/fr
Publication of EP1121786A4 publication Critical patent/EP1121786A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/64—Hybrid switching systems
    • H04L12/6418—Hybrid transport
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M7/00—Arrangements for interconnection between switching centres
    • H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
    • H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
    • H04M7/1295—Details of dual tone multiple frequency signalling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/64—Hybrid switching systems
    • H04L12/6418—Hybrid transport
    • H04L2012/6475—N-ISDN, Public Switched Telephone Network [PSTN]

Definitions

  • the present invention relates to methods for signal processing based on detection of tones in a digital or analog signal. More specifically, the present invention relates to signal processing between detection and confirmation of specified signals within a digitized signal stream which includes a mixture of signals.
  • Analog signals such as voice are often compressed through application of codecs during conversion to digital data or form for transmission.
  • codecs to compress the information into digital form allows for enhanced transfer through reducing the size of the data.
  • voice can be compressed and restored through application of a codec with minimal degradation in the integrity of the comprehension of the sound, even with the use of low byte rate codecs. Accordingly, low byte rate codecs are often used to compress voice, especially in voice over packet network applications.
  • ITU Recommendation H.323 is a standard approved by the International Telecommunication Union (ITU) that defines how audiovisual conferencing data is transmitted.
  • ITU Recommendation H. 323 is a standard approved by the International Telecommunication Union (ITU) that defines how audiovisual conferencing data is transmitted.
  • Tones are detected and identified initially at the transmission side, before encoding, and the identity of the tone is sent out of band as a control message between two ends of a connection using reliable transport (TCP) mechanisms.
  • TCP reliable transport
  • the DTMF tone is regenerated at the receiving end without distortion.
  • identification and recognition of the tone must be established for a set period of time to avoid false generation of tones.
  • the regenerated tones are out of synchronization with the voice path because of differential delay through the transmission medium because each travels overa different data path. Therefore, the out of band control signal or tone is not in synchronization with the voice packets.
  • a DTMF detector typically takes about 30-40 milliseconds (m ⁇ ) to fully qualify DTMF tones.
  • ITU Q.24 requires that a DTMF signal be present for 30ms before being declared a digit.
  • the voice channel is squelched upon detection of a DTMF tone and the DTMF tone is passed through the out of band channel. Accordingly, a remote detector is triggered by this out of band DTMF and recognizes it as a digit entry. If any portion of the DTMF tone is leaked through the voice path, the remote detector might be triggered by this leaked DTMF. Since the leaked tone would present first to the remote detector, the later received out of band tone may cause a second detection for a single digit entry.
  • One method for reducing double detection is the introduction of a 30-40ms delay in the voice path.
  • a sufficient delay in the voice path will allow the voice path to be squelched upon detection, before the tone has passed over the voice path packets.
  • any delay introduced into the voice path is highly undesirable since this will increase the end to end delay in the system. Accordingly, it is desirable to develop a method for detecting tones in a voice signal prior to transmitting the voice signal through the network and without introducing undue delay in the transmission.
  • the present invention further allows for reliable transport of tones through a control channel, without causing false detections on the remote end, or unnecessarily increasing the end to end delay.
  • a tone detection unit into the network for providing early detection of control tones.
  • the method incorporates the use of the tone detection unit in combination with a packet voice protocol unit.
  • the tone detection unit Upon transmission of the voice signal, the tone detection unit generates an alert signal to the packet voice protocol unit after an initial detection of a control tone for a 5 s duration.
  • the Packet Voice Protocol Unit (PVPU) ceases sending any additional voice packets until confirmation of the control tone is received.
  • the voice packets may either be buffered for later transmission if it is determined that the alert signal was premature, or dropped in the event confirmation of the control tone is received.
  • the Tone Detection Unit (TDU) in combination with the PVPU function to provide an early alert process for detection of control tones in a signal transmission without causing undue delay in the event transmission of the alert signal was improper.
  • Figure 1 is a block diagram illustrating the components of a typical voice over packet transmission circuit.
  • Figure 2 is an exemplary logic flow diagram illustrating the signal timing of an exemplary embodiment of the present invention.
  • DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS AND BEST MODE OF THE INVENTION In a preferred embodiment of the present invention, a signal representing a human voice is transmitted through a network.
  • a TDU and a PVPU are utilized to determine the presence of any control tones in the transmission, and to prevent transmission of the control tones in the voice packet as early detection of control tones in the transmission signal is desirable to avoid delay in the transmission.
  • the present invention takes advantage of the early initial detection by the TDU and generates an Alert signal to the Packet Voice Protocol Unit (PVPU) shortly after detection of any tones, but prior to confirmation of the tone.
  • the PVPU stops sending voice packets instead of waiting for confirmation.
  • the PVPU may simply drop the packets after the Alert signal or may buffer the packets for later transmission if the tone is not qualified or confirmed.
  • the TDU also sends the out of band tone detect message and the tone for transmission via Transmission Control Protocol (TCP) to the receiving side.
  • TCP Transmission Control Protocol
  • the tone is not qualified or confirmed within a certain timeout period after the Alert message, voice transmission is resumed, and all of the buffered packets are then transmitted.
  • the resumption of voice packet transmission is desirable to avoid delay in the transmission.
  • Implementation of the present invention may add delay or jitter to voice transmission in limited instances when false early detection occurs.
  • the present invention may also result in interruption and loss of voice if a buffer is not utilized when a tone is falsely detected.
  • false tone detection is uncommon and the loss or delay of 5-30ms of voice will not cause significant distortion in voice over packet transmission to negate the desirable effect of early detection of control tones.
  • DTMF detectors are typically aware of the presence of DTMF digits for the entire duration of qualification.
  • the qualification duration period is established to reduce the false detection of DTMF digits.
  • the present invention makes use of the early detection of DTMF digits prior to qualification to act proactivly and stop sending voice to the network as soon as the DTMF detector believes that there is the possibility of a DTMF digit.
  • the DTMF detector (not shown) in the TDU 11 waits for a tone 21 upon transmission of a signal.
  • the DTMF detector in the TDU 11 sends an Alert signal 23 to the PVPU 12.
  • the PVPU 12 may either terminate transmission of the voice packets 24 thereby ceasing transmission of voice packets to the network, or the PVPU 12 may buffer the voice packets 25 for later transmission. Regardless of either the termination or buffering of the voice packets, all transmission of voice packets to the network ceases upon receipt of an early tone detection. Following generation of the alert signal 23 indicating possible presence of DTMF digits, the PVPU 12 must wait for qualification of DTMF digits 26. In the event that the DTMF digit is qualified 27, typically after 30-40ms, the DTMF detector in the TDU 11 sends a Detect On signal 28 to the PVPU 12 and any buffered packets are dropped 31, and the voice channel remains off.
  • the PVPU 12 also sends the out of band DTMF detect message 30 for transmission via TCP to the receiving side of the transmission and the PVPU 12 waits for termination of the DTMF 34.
  • the TDU sends a Detect Off signal 33 to the PVPU 12 and transmission of voice to the packet network is resumed 35.
  • the TDU 11 returns to the waiting mode for a tone state 21.
  • the voice transmission resumes 35, including transmission of all of the buffered packets 37.

Abstract

L'invention concerne un procédé de détection de tonalités de commande dans un signal numérique faisant appel à une unité de détection de tonalité (11) (TDU) et à une unité à protocole de transmission de la voix par paquets (12) (PVPU) dans un réseau sur lequel le signal est émis. L'unité de détection de tonalité (11) (TDU) détecte la présence d'une tonalité de commande dans le signal, dans les 5 premières ms de l'émission, et génère un signal d'alerte (3) qu'elle envoie à l'unité à protocole de transmission de la voix par paquets (12) (PVPU) pour qu'elle mette fin à l'émission du signal. Sur confirmation, ladite unité à protocole de transmission de la voix par paquets (12) (PVPU) arrête l'émission et stocke provisoirement ou annule les paquets de signaux vocaux. Selon une variante, si les tonalités de commande ne sont pas présentes dans le signal, l'unité à protocole d'émission de la voix par paquets (12) (PVPU) peut continuer l'émission de paquets quelconques stockés provisoirement. Le procédé comprend également l'émission du signal de tonalité de commande à l'extrémité réceptrice des paquets vocaux émis après l'émission de la tonalité de commande vers l'extrémité réceptrice.
EP99941106A 1999-08-12 1999-08-13 Identification de dtmf rapide Withdrawn EP1121786A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US37420399A 1999-08-12 1999-08-12
US374203 1999-08-12
PCT/US1999/018401 WO2001013586A1 (fr) 1999-08-12 1999-08-13 Identification de dtmf rapide

Publications (2)

Publication Number Publication Date
EP1121786A1 true EP1121786A1 (fr) 2001-08-08
EP1121786A4 EP1121786A4 (fr) 2007-05-30

Family

ID=23475770

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99941106A Withdrawn EP1121786A4 (fr) 1999-08-12 1999-08-13 Identification de dtmf rapide

Country Status (4)

Country Link
EP (1) EP1121786A4 (fr)
JP (1) JP2003507933A (fr)
AU (1) AU5482499A (fr)
WO (1) WO2001013586A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7035293B2 (en) * 2001-04-18 2006-04-25 Broadcom Corporation Tone relay
US20030194082A1 (en) 2002-04-15 2003-10-16 Eli Shoval Method and apparatus for transmitting signaling tones over a packet switched network
CN102790958B (zh) * 2012-06-29 2016-03-30 华为终端有限公司 一种传输信令的方法及装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5666357A (en) * 1995-03-23 1997-09-09 Hughes Electronics DTMF tone passer in a voice communication system

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1268570A (fr) * 1987-08-14 1990-05-01 Melvin J. Roberts Detecteur de tonalites telephoniques
US5295178A (en) * 1990-12-03 1994-03-15 Ericsson Ge Mobile Communications Inc. Digital signal processor for radio base station
US5721729A (en) * 1996-01-24 1998-02-24 Klingman; Edwin E. Universal input call processing system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5666357A (en) * 1995-03-23 1997-09-09 Hughes Electronics DTMF tone passer in a voice communication system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO0113586A1 *

Also Published As

Publication number Publication date
JP2003507933A (ja) 2003-02-25
EP1121786A4 (fr) 2007-05-30
AU5482499A (en) 2001-03-13
WO2001013586A1 (fr) 2001-02-22

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Inventor name: PATEL, PIYUSH

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