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Topic: Dual tone multi frequency

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Touch tone

Autovon

Dial tone

Automatic telephone exchange

Pulse dialing

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Blue box

Ringing signal

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Harmonic series (music)

Musical tuning

Whole tone

Dual-tone multi-frequency - Wikipedia, the free encyclopedia DTMF is an example of a multifrequency shift keying (MFSK) system. The frequencies were initially designed with a ratio of 21/19, which is slightly less than a whole tone. The trunk signalling tones were different from the tones known as touch tone with a triangular matrix being used rather than a square matrix. en.wikipedia.org /wiki/Dual_tone_multi_frequency   (984 words)

Dual Tone Multi-Frequency (Touch-Tone®) Reference Dual Tone Multi-Frequency, or DTMF is a method for instructing a telephone switching system of the telephone number to be dialed, or to issue commands to switching systems or related telephony equipment. The DTMF dialing system traces its roots to a technique ATandT developed in the 1950s called MF (Multi-Frequency) which was deployed within the ATandT telephone network to direct calls between switching facilities using in-band signaling. The energy strength of the high-group frequency must be -8 dB to +4 dB relative to the energy strength of the low-group frequency as measured at the receiver. nemesis.lonestar.org /reference/telecom/signaling/dtmf.html   (1699 words)

DTMF also known as Touch Tone The frequencies were chosen to avoid harmonics (no frequency is a multiple of another, the difference between any two frequencies does not equal any of the frequencies, and the sum of any two frequencies does not equal any of the frequencies). When any key is pressed the tone of the column and the tone of the row are generated, hence dual tone. The frequencies generated must be with +/- 1.5%, the highest frequency must be as loud as the lowest frequency and as much as 4db louder. www.shout.net /~wildixon/telecom/dtmf/dtmf.html   (224 words)

29085.990610&ELEMENT_SET=DECL In the normal course of tone detection it may occur that a speech utterance is mistaken for a tone, that a tone is not detected or that a given tone is mistaken for another. The correct detection of a tone by the receiver implies that the signal originating from a transmitter station is accurately decoded by the receiver as being the transmitted tone. Tone receiver systems have been developed in many parts of the world and, although it is difficult to describe a standard tone receiver architecture, some characteristics are shared between many of them. www.wipo.int /cgi-pct/guest/getbykey5?KEY=99/29085.990610&ELEMENT_SET=DECL   (9559 words)

DTMF - Dual Tone MultiFrequency Dual tone multi- frequency: commonly known as touch-tone or push-button dialing, as opposed to older-style pulse or rotary dialing. Dual Tone Multifrequency Signaling (communications) Signaling system used to send numeration in classical analogical switching systems. Upon pressing the keypad on your telephone a tone is produced (a combination of a high + low frequency pulse) that defines the number pressed. www.auditmypc.com /acronym/DTMF.asp   (627 words)

Dual tone multi frequency digital detector - Patent 4484035 In an eight tone frequency regime of four low frequencies (697 hz, 770 hz, 852 hz and 941 hz) and four high frequencies (1209 hz, 1336 hz, 1477 hz and 1633 hz)) combinations of paired tones, one from each group, are detected. Frequencies outside of the specified tones by a margin exceeding 3.5 percent cannot be passed with the prescribed ratio of 8/10 of the long time span signal to the short time signal. For example, and considering the 941 hz output, a division value of 1,063 an integer is determined with an optimum frequency of 940.73 being the actual frequency examined. www.freepatentsonline.com /4484035.html   (6891 words)

DTMF - a Whatis.com definition - see also: DTMF, dual tone multi frequency DTMF (dual tone multi frequency) is the signal to the phone company that you generate when you press an ordinary telephone's touch keys. DTMF - a Whatis.com definition - see also: DTMF, dual tone multi frequency So that a voice can't imitate the tones, one tone is generated from a high-frequency group of tones and the other from a low frequency group. searchnetworking.techtarget.com /sDefinition/0,,sid7_gci213922,00.html   (217 words)

DTMF Basics - HW server - dtmf,basics,dual-tone multi frequency,dual,tone,multi,frequency,modem,telephony,cb,transceiver,floating,code,mobile,cellular,phone,frekquency,decoder DTMF (Dual-tone Multi Frequency) is a tone composed of two sine waves of given frequencies. Individual frequencies are chosen so that it is quite easy to design frequency filters, and so that they can easily pass through telephone lines (where the maximum guaranteed bandwith extends from about 300 Hz to 3.5 kHz). DTMF was designed so that it is possible to use acoustic transfer, and receive the codes using standard microphone. www.hw-server.com /docs/dtmfb.html   (655 words)

Dual Tone Multi-Frequency (DTMF) Generation and Detection Software - GAO Research GAO's Dual Tone Multi-Frequency (DTMF) Software is an implementation of a Dual-Tone Multi-Frequency (DTMF) generator and decoder. Rigorous Testing on Dual Tone Multi-Frequency (DTMF) Software Dual Tone Multi-Frequency (DTMF) Generation and Detection Software - GAO Research www.gaoresearch.com /products/telephony/other/dtmf.php   (354 words)

05905.000203&ELEMENT_SET=DECL A dual-tone multi-frequency (DTMF) and audio controller detects a DTMF signal in the audio signal, removes the DTMF signal from the audio signal and generates a delay in the audio signal. The DTMF tone data is output to the DTMF/audio multiplexer 136 where the DTMF tone data is injected into the audio stream. The DTMF/audio controller 120 analyzes the G. audio data for data bytes and strings of data bytes that correspond to a digitized tone having a frequency matching the combination of the low and high frequencies of the DTMF tones. www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/05905.000203&ELEMENT_SET=DECL   (12603 words)

dtmfdemo.m % % Dual-tone Multi-Frequency (DTMF) signaling is the basis for voice % communications control and is widely used worldwide in modern telephony % to dial numbers and configure switchboards. %% Dual-Tone Multi-Frequency (DTMF) Signal Detection % This demonstration showcases the use of the Goertzel function as a part % of a DFT-based DTMF detection algorithm. These frequencies % were chosen to prevent any harmonics from being incorrectly detected % by the receiver as some other DTMF frequency. www.clemson.edu /cle4_share/CWE/COES0915_CLUG/REFERENCE/matlabr14/toolbox/signal/sigdemos/dtmfdemo.m   (532 words)

biology - Tone Dual-tone multi-frequency or tone dialing (as opposed to pulse dialing) A semitone is half a whole tone or a minor second, the ratio 16:15, or the interval 1. Interval (music) - A whole tone is the difference in pitch between notes two semitones apart, also referred to as major second, the ratio 9:8 (just intonation), or in atonal or set theory an interval of 2. www.biologydaily.com /biology/Tone   (250 words)

Junior's 2000 In telephones equipped with TOUCH-TONE dialing, the pressing of each button generates a unique set of dual tone multi-frequency (DTMF) signals that are processed at the telephone central office to identify the number pressed by determining the two associated tone frequencies. Specifically, no frequency is a multiple of another, the difference between any two frequencies does not equal any of the frequencies, and the sum of any two frequencies does not equal any of the frequencies. For example, pressing the 5 button generates a signal consisting of tones at 770 Hz and 1336 Hz. www.loyola.edu /academics/alldepartments/engineeringscience/junior00.html   (604 words)

DTMF Dual-tone-multi-frequency (DTMF, also known as touch-tone) are the audible sounds you hear when you press keys on your phone. Each tone is the sum of two frequencies: one from a low and one from a high frequency group. The frequency of the tone is about 1900 Hz - close to the 1906 Hz predicted by Table 3 (697+1209). www.boondog.com /tutorials/dtmf/dtmf.htm   (1720 words)

3GPP specification CRs: 23.014 Dual Tone Multi-Frequency signalling: Support in the whole 3GPP system, and editorial modifications. www.3gpp.org /ftp/specs/html-info/23014-CRs.htm   (84 words)

Technisch artikel over DTMF Dual Tone Multi-frequency dual tone is created each of which generates a unique frequency. DTMF stands for Dual Tone/Mutli-Frequency and it is the process by which When a button is it on a TouchTone(c) phone a www.aardbaan.com /phreak/doc_artikelen_dtmf1.php   (823 words)

For sound and other information on “dual tone multi-frequency” dialing: For sound and other information on “dual tone multi-frequency” dialing: Use the DTMF frequency standards (1.a above) and spreadsheet (1.b) to generate waveforms for the tones corresponding to the ten numeric characters of a typical telephone keypad. As “homework”, later obtain a copy of the audio tone freeware (1.c above) and use it, along with the DTMF information (1.a above) to generate and save (in WAV format) audio tone files for each digit in the suspect phone number. www.uncp.edu /home/pwf/151sound.htm   (297 words)

LM2430 The Comtrol Dual Tone Multi Frequency (DTMF) Transmitter is used in conjunction with Comtrol’s DTMF visual receiver or Comtrol’s DTMF LoudMouth. LM2430 - Dual Tone Multi Frequency (DTMF) Transmitter Dual NEDA 926 batteries for extended service or intrinsically safe power supply. www.comtrol-corp.com /lm2430.htm   (152 words)

Dual Tone Multi Frequency DTMF is standardized in CCITT recommandation Q.23 and in CEPT recommandation T/CS 46-02. DTMF uses two groups of four frequencies each. Each combination of two frequencies defines a symbol. utopia.knoware.nl /users/eprebel/Communication/DTMF.html   (43 words)

DTMF: Dual Tone Multi Frequency Talk Back includes a Dual Tone Multi Frequency feature so that it can generate telephone dialling tones for the keypad characters 0 to 9, A to F, star, and hash. Electronic Touchtone phones generate DTMF tones which are sent to the telephone exchange as you press the keys. A human voice, or a simple beeper, can't copy them because each key generates two specific frequencies: one from a low frequency group of four and one from a higher frequency group of four, making a total of sixteen possible combinations. www.talking.co.uk /dtmf.htm   (622 words)

TOSHIBA ANNOUNCES 8-BIT MCUs WITH DUAL-TONE The new devices, designated TMP87CM53F and TMP87PM53F, feature a Dual-Tone Multi Frequency (DTMF) function, which makes them ideal for digital telephone and telecommunications applications. The incorporation of DTMF in these MCUs brings key system benefits including single/dual tone generator with low distortion (CEPT CS203 compatible), melody (sine or square wave) generation, single/dual clock, and five power-saving modes including STOP, SLOW, IDLE 1, IDLE 2 and SLEEP for low power consumption that is ideal for hand-held battery operated products. The devices have 32 kilobytes (KB) of on-board ROM and 1KB of on-board RAM, and are equipped with 15 interrupt sources, 72-pin I/O port and a single/dual clock mode. www.toshiba.com /taec/press/to-608.shtml   (567 words)

.: UNEASYsilence :. » How-to: Phreaking your iPod (DTMF) Using these tones will - in theory - grant you special access to switch functions through telephone carriers. can somebody email me those tones because i’m using my school’s computers, which blocks out this type of stuff. Due to the highly illegal nature of creating any one of these dialers, I won’t go into the actual details required to turn your iPod - or any other MP3 player - into a tone dialer. www.uneasysilence.com /archive/2005/05/3065   (328 words)

Western Electric Products - Telephones - Table of Contents The dial tone has the same meaning as the manual switchboards operator's "Number, please." It means the: switching equipment is ready to handle your call and you can now dial your number. Old dial tone consists of 600 Hz modulated by 120 Hz when supplied by a tone alternator or 133Hz when supplied by an interrupter. As digits are received by senders, switching equipment move: into action by causing brass rods with multiple brushes or wipers to move upward on banks of term'‑.pals to locate air available trunk to the office or number called. www.bellsystemmemorial.com /telephones.html   (3844 words)

dual tone multi-frequency (DTMF) Each key generates two tones of specific frequencies, one high and one low. Describes the signal that is generated when a telephone’s touch keys are pressed. www.milgo.com /manuals/TimePlex/IAN15020/ian15013dual_tone_multifrequency_DTMF.htm   (26 words)

Dual Tone Multi Frequency SPIRIT's DTMF (Detector & Generator) conforms to ITU-T Q.23 recommendation and is used to detect and generate all 16 DTMF digits under a broad range of network conditions. Signal frequencies used: 697, 770, 852, 941, 1209, 1336, 1477, 1633 Hz. It consists of two main parts: DTMF detector and DTMF generator. www.spiritcorp.com /dtmf.html   (198 words)

Publication of Dual Tone Multi-Frequency Signalling Specifications The title of the ETSI TS (Technical Specification) is: Specification of Dual Tone Multi Frequency Transmitters and Receivers For instance, it was always implied that the DTMF senders were external units to Terminal Equipment, which is not the case today. ETSI TS 101 235-3 Receivers - Requirements for the DTMF receiver for the case of DTMF signalling over the subscribers local loop, i.e. www.etsi.org /t_news/0006_ata.htm   (355 words)

US06845356-20050118.html A system for converting dual tone multi-frequency signals into text equivalents for use with a natural language understanding system said system comprising: Processing dual tone multi-frequency signals for use with a natural language understanding system an interactive voice response unit for receiving user inputs comprising user spoken utterances and dual tone multi-frequency signals; www.uspto.gov /web/patents/patog/week03/OG/html/1290-3/US06845356-20050118.html   (94 words)

DTMF.ppt This project (code) can also be improved for Multi channel DTMF. www.wright.edu /~shankar.2/DTMF.ppt   (202 words)

US06914968-20050705.html applying the constant Dual Tone Multi-Frequency signal to the telephone line, whereby Dual Tone Multi-Frequency dialing cannot take place on the telephone line, and generating a constant Dual Tone Multi-Frequency signal in response to detecting one or more Dual Tone Multi-Frequency signals; detecting one or more Dual Tone Multi-Frequency signals on the telephone line; www.uspto.gov /web/patents/patog/week27/OG/html/1296-1/US06914968-20050705.html   (168 words)

What is Dual Tone Multi Frequency? - A Word Definition From the Webopedia Computer Dictionary For internet.com pages about Dual Tone Multi Frequency You are in the: Small Business Computing Channel www.webopedia.com /TERM/D/Dual_Tone_Multi_Frequency.html   (33 words)

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