787:
1489:
879:
654:
1082:: The Society of Cable Television Engineers (SCTE) reported that many cable systems have installed Dual Tone Multi-Frequency (DTMF) signalling equipment between the cable system and local officials for use in transmitting emergency information as part of the local franchise agreement. The SCTE recommended that DTMF decoding be incorporated in the new equipment since it is already used by many cable systems. The new
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54:
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286:
AT&T described the product as "a method for pushbutton signaling from customer stations using the voice transmission path". In order to prevent consumer telephones from interfering with the MF-based routing and switching between telephone switching centers, DTMF frequencies differ from all of the
381:
is laid out as a matrix of push buttons in which each row represents the low frequency component and each column represents the high frequency component of the DTMF signal. The commonly used keypad has four rows and three columns, but a fourth column is present for some applications. Pressing a key
1038:
for the insertion of up to a maximum of twelve (12) minutes per hour of commercial advertising time. Until such cue tones are delivered or at any time thereafter upon DISH's request, DISH may deliver all or part of its
Advertising Allocation to Network via FTP or courier, at Network's sole cost and
810:
to DTMF decoding has been shown to outperform
Goertzel and being the only possibility in cases when number of available samples is limited. As DTMF signaling is often transmitted in-band with voice or other audio signals present simultaneously, the DTMF signal definition includes strict limits for
214:
as it spins back to its rest position after having been rotated to each desired number. The exchange equipment responds to the dial pulses either directly by operating relays or by storing the number in a digit register that records the dialed number. The physical distance for which this type of
1086:
code protocol will be a national standard and should exceed the capabilities of DTMF. Local emergency managers will find the EAS equipment much more flexible than DTMF equipment. For example, they will be able to access EAS equipment at cable headends directly. The emergency messages in the EAS
271:
to input the next portion of the destination telephone number in order to contact the next downstream long-distance telephone operator. This semi-automated signaling and switching proved successful in both speed and cost effectiveness. Based on this prior success with using MF by specialists to
762:
videocassettes. Information on the master version of the video tape is encoded in the DTMF tones. The encoded tones provide information to automatic duplication machines, such as format, duration and volume levels in order to replicate the original video as closely as possible.
348:
equipment was developed in the 1990s, fast, unacknowledged DTMF tone sequences could be heard during the commercial breaks of cable channels in the United States and elsewhere. Previously, terrestrial television stations used DTMF tones to control remote transmitters. In
739:
used signals A, B, C, and D to assert certain privilege and priority levels when placing telephone calls. Precedence is still a feature of military telephone networks, but using number combinations. For example, entering 93 before a number is a priority call.
283:. As the signals are audible tones in the voice frequency range, they can be transmitted through electrical repeaters and amplifiers, and over radio and microwave links, thus eliminating the need for intermediate operators on long-distance circuits.
390:
low tone and a 1209 Hz high tone. Initial pushbutton designs employed levers, enabling each button to activate one row and one column contact. The tones are decoded by the switching center to determine the keys pressed by the user.
215:
dialing was possible was restricted by electrical distortions and was possible only on direct metallic links between end points of a line. Placing calls over longer distances required either operator assistance or provision of special
673:
747:
is used in some networks for cycling through a list of carriers. The signals are used in radio phone patch and repeater operations to allow, among other uses, control of the repeater while connected to an active telephone line.
823:
National telephone systems define other tones, outside the DTMF specification, that indicate the status of lines, equipment, or the result of calls, and for control of equipment for troubleshooting or service purposes. Such
708:
or "star" (*) keys as well as a group of keys for menu selection: A, B, C and D. In the end, the lettered keys were dropped from most keypads and it was many years before the two symbol keys became widely used for
1052:"In the Matter of Amendment of Part 73, Subpart G, of the Commission's Rules Regarding the Emergency Broadcast System, REPORT AND ORDER AND FURTHER NOTICE OF PROPOSED RULE MAKING, B. Cable participants § 63,65"
619:
696:
Engineers had envisioned telephones being used to access computers and automated response systems. They consulted with companies to determine the requirements. This led to the addition of the
593:
632:
606:
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492:
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353:, DTMF signals can also be delivered as either in-band or out-of-band tones, or even as a part of signaling protocols, as long as both endpoints agree on a common approach to adopt.
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936:
275:
The DTMF system uses a set of eight audio frequencies transmitted in pairs to represent 16 signals, represented by the ten digits, the letters A to D, and the symbols
303:
was made available to the public. As a parent company of Bell
Systems, AT&T held the trademark from September 4, 1962, to March 13, 1984. It is standardized by
2532:
2504:
2499:
1524:
811:
timing (minimum duration and interdigit spacing), frequency deviations, harmonics, and amplitude relation of the two components with respect to each other (
755:
operators and commercial two-way radio systems for equipment control, repeater control, remote-base operations and some telephone communications systems.
3011:
2616:
272:
establish long-distance telephone calls, dual-tone multi-frequency signaling was developed for end-user signaling without the assistance of operators.
2955:
61:
keypads were one of the few production units to include all 16 DTMF signals. The red keys in the fourth column produce the A, B, C, and D DTMF events.
1308:
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672:
344:
to indicate the start and stop times of local commercial insertion points during station breaks for the benefit of cable companies. Until
299:. The term was first used by AT&T in commerce on July 5, 1960, and was introduced to the public on November 18, 1963, when the first
2760:
2516:
2362:
1460:
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Before the development of DTMF, telephone numbers were dialed by users with a loop-disconnect (LD) signaling, more commonly known as
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Present-day uses of the signals A, B, C and D are rare in telephone networks, and are exclusive to network control. For example,
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are often also composed of multiple frequencies and are standardized in each country. The Bell System defined them in the
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1207:"P. Gregor, Application of MUSIC algorithm to DTMF detection, Engineering Thesis, Warsaw University of Technology, 2022"
152:
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2070:
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1990:
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866:
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and has become the industry standard in telephony to control automated equipment and signal user intent. Other
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1995:
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318:. Automatic Electric (GTE) referred to it as "Touch-calling" in their marketing. Other trade names such as
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2020:
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1034:: Within four (4) months after the Launch Date, Network shall deliver the Signal with industry standard
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systems to transfer the caller ID information, a function that is performed in the United States by
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expense, and
Network shall insert such Advertising Allocation at Network's sole cost and expense.
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1015:"DISH NETWORK L.L.C., INTERNATIONAL AFFILIATION AGREEMENT: Metro Media Holding Corp (Filer)"
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became the predominant technology for decoding. DTMF decoding algorithms typically use the
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2040:
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1152:
Shady
Characters: The Secret Life of Punctuation, Symbols, and Other Typographical Marks
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2110:
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2015:
1890:
1725:
1611:
1341:
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771:
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700:(#, ''pound'' or "diamond" in this context, "hash", "square" or "gate" in the UK, and "
202:(dial pulse, DP) in the United States. It functions by interrupting the current in the
1322:"Human Factors Engineering Studies of the Design and Use of Pushbutton Telephone Sets"
210:'s telephone at a precise rate with a switch in the telephone that is operated by the
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2065:
1955:
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that accept credit cards use these additional codes to send the information from the
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1970:
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DTMF signaling tones may also be heard at the start or end of some prerecorded
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Other vendors of compatible telephone equipment called the Touch-Tone feature
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digital signaling. DTMF was known throughout the Bell System by the trademark
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supplied to telephone customers, starting in 1963. DTMF is standardized as
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2005:
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sends a combination of the row and column frequencies. For example, the
190:
systems are also used for signaling on trunks in the telephone network.
115:
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2796:
2445:
2430:
1364:
ITU-T Recommendation Q.24 - Multifrequency push-button signal reception
1363:
950:
732:
369:
254:
58:
287:
pre-existing MF signaling protocols between switching centers: MF/R1,
2816:
2475:
2435:
1757:
1549:
1502:
1176:
847:
were based on touch-tone frequencies, such as Bell 400-style modems.
268:
2894:
2594:
1117:
Session
Initiation Protocol (SIP) INFO Method and Package Framework
1104:
RTP Payload for DTMF Digits, Telephony Tones, and
Telephony Signals
751:
The signals *, #, A, B, C and D are still widely used worldwide by
373:
Combination of 1209 Hz and 697 Hz sine waves, representing DTMF "1"
147:
system using the voice-frequency band over telephone lines between
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1705:
844:
785:
387:
368:
360:
304:
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104:
30:"Tone dialing" redirects here. For the Ornette Coleman album, see
2402:
1087:
protocol will also be available to local broadcast stations and
965:"What is DTMF (dual tone multi-frequency) and how does it work?"
2898:
2598:
1506:
1372:
3052:
2837:
2811:
1648:
759:
1021:. 27 January 2016. S.E.C. Accession No. 0001557234-16-000400
652:
233:) is a group of signaling methods that use a mixture of two
159:
in the United States, and became known under the trademark
1278:"Pushbutton Calling with a Two-Group Voice-Frequency Code"
1242:
Subscriber Loop
Signaling and Transmission Handbook—Analog
307:
Recommendation Q.23. In the UK, it is also known as MF4.
713:
such as *67 in the United States and Canada to suppress
1139:). Section "400-Style (Touch-Tone) Modems". p. 177-178.
907:(5th ed.). Upper Saddle River, NJ: Prentice Hall.
291:, CCS4, CCS5, and others that were later replaced by
1271:
ITU's recommendations for implementing DTMF services
1195:. Intertec Publishing Corporation], $ 4c 1959. 1983.
3035:
3004:
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2743:
2705:
2632:
2484:
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1848:
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171:Recommendation Q.23. It is also known in the UK as
110:
100:
82:
74:
66:
1358:Dual Tone Multi-Frequency (Touch-Tone) Reference
951:Technical features of push-button telephone sets
151:equipment and other communications devices and
2910:
2610:
1518:
1384:
219:equipment. Operators used an earlier type of
8:
1127:
1125:
935:: CS1 maint: multiple names: authors list (
46:
2533:Global telecommunications regulation bodies
395:DTMF keypad frequencies (with sound clips)
257:signaling between switching centers, where
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2895:
2617:
2603:
2595:
2569:
1525:
1511:
1503:
1391:
1377:
1369:
52:
45:
905:The essential guide to telecommunications
393:
386:key produces a superimposition of a 697
1177:""What are the ABCD tones?" — Tech FAQ"
1019:U.S. Securities and Exchange Commission
895:
206:between the telephone exchange and the
1223:
1212:
928:
686:
794:DTMF was originally decoded by tuned
7:
2579:
1149:Houston, Keith (24 September 2013).
953:(Report). Recommendation. ITU. Q.23.
1115:C. Holmberg, E. Burger, H. Kaplan,
137:Dual-tone multi-frequency signaling
47:Dual-tone multi-frequency signaling
2777:American Telephone & Telegraph
1342:10.1002/j.1538-7305.1960.tb04447.x
1297:10.1002/j.1538-7305.1960.tb03929.x
1091:offices for further dissemination.
798:. By the end of the 20th century,
704:'' by the original engineers) and
155:. DTMF was first developed in the
27:Telecommunication signaling system
25:
1285:The Bell System Technical Journal
1063:Federal Communications Commission
333:, DTMF signals were also used by
253:. The earliest of these were for
2578:
2568:
2559:
2558:
2547:
2168:Free-space optical communication
1487:
1320:Deininger, R.L. (July 4, 1960).
877:
819:Other multiple frequency signals
790:Two CMD CM8870CSI DTMF Receivers
687:Problems playing this file? See
668:
1314:from the original on 2012-03-14
1106:, IETF RFC 4733, December 2006.
241:) sounds. Various MF signaling
1400:Signaling (telecommunications)
1119:, IETF RFC 6086, January 2011.
1102:H. Schulzrinne and T. Taylor,
989:Compatibility Bulletin No. 105
679:audio output of a DTMF signal.
182:gradually replaced the use of
1:
1326:Bell System Technical Journal
2554:Telecommunication portal
2335:Telecommunications equipment
1155:. W. W. Norton. p. 45.
766:DTMF tones are used in some
628:
615:
602:
589:
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571:
558:
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529:
514:
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475:
472:
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410:
407:
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401:
399:
2071:Alexander Stepanovich Popov
1065:. 9 December 1994. p.
145:telecommunication signaling
88:; 61 years ago
3095:
1775:Telecommunications history
903:Z., Dodd, Annabel (2012).
737:United States Armed Forces
178:Touch-tone dialing with a
36:
29:
2542:
2383:Public Switched Telephone
2195:telecommunication circuit
2156:Fiber-optic communication
1901:Francis Blake (telephone)
1696:Optical telecommunication
1484:
1466:Multi-frequency signaling
1461:Dual-tone multi-frequency
1406:
1255:Notes on Distance Dialing
1080:Dual Tone Multi-Frequency
834:Multi-frequency signaling
800:digital signal processing
324:Northern Electric Company
227:Multi-frequency signaling
51:
2294:Orbital angular-momentum
1731:Satellite communications
1570:Communications satellite
1441:Special information tone
1133:"TV Typewriter Cookbook"
867:Special information tone
806:although application of
735:telephone system of the
217:subscriber trunk dialing
194:Multifrequency signaling
37:For the video game, see
2173:Molecular communication
1996:Gardiner Greene Hubbard
1825:Undersea telegraph line
1560:Cable protection system
1476:Signalling System No. 7
2697:Design Line telephones
2315:Communication protocol
2101:Charles Sumner Tainter
1916:Walter Houser Brattain
1861:Edwin Howard Armstrong
1669:Information revolution
1471:Signaling System No. 5
1222:Cite journal requires
791:
776:frequency-shift keying
711:vertical service codes
657:
374:
366:
165:push-button telephones
3079:Broadcast engineering
2869:Bell System Practices
2782:AT&T Technologies
2756:Orthophonic recording
2289:Polarization-division
2021:Narinder Singh Kapany
1986:Erna Schneider Hoover
1906:Jagadish Chandra Bose
1886:Alexander Graham Bell
1617:online video platform
1494:Telephones portal
1192:Broadcast Engineering
884:Telephones portal
789:
656:
372:
364:
346:out-of-band signaling
301:push-button telephone
2131:Vladimir K. Zworykin
2091:Almon Brown Strowger
2061:Charles Grafton Page
1716:Prepaid mobile phone
1644:Electrical telegraph
1276:Schenker, L (1960),
646:#, *, A, B, C, and D
245:were devised by the
32:Tone Dialing (album)
2807:Lucent Technologies
2081:Johann Philipp Reis
1840:Wireless revolution
1802:The Telephone Cases
1659:Hydraulic telegraph
1244:, IEEE (1992), p.27
826:call-progress tones
396:
262:telephone operators
48:
2833:Automatic Electric
2279:Frequency-division
2256:Telephone exchange
2126:Charles Wheatstone
2056:Jun-ichi Nishizawa
2031:Innocenzo Manzetti
1966:Reginald Fessenden
1701:Optical telegraphy
1534:Telecommunications
804:Goertzel algorithm
792:
658:
394:
375:
367:
365:DTMF keypad layout
3074:Telephony signals
3061:
3060:
3005:Related standards
2892:
2891:
2874:Eastland disaster
2853:Stromberg-Carlson
2817:Northern Electric
2770:Related companies
2707:Switching systems
2592:
2591:
2330:Store and forward
2325:Data transmission
2239:Network switching
2190:Transmission line
2036:Guglielmo Marconi
2001:Internet pioneers
1866:Mohamed M. Atalla
1835:Whistled language
1500:
1499:
1162:978-0-393-24154-9
862:Selective calling
857:In-band signaling
836:was exploited by
830:Precise Tone Plan
808:MUSIC (algorithm)
778:(FSK) signaling.
674:
643:
642:
331:in-band signaling
322:were used by the
153:switching centers
134:
133:
16:(Redirected from
3086:
2919:
2912:
2905:
2896:
2744:Other technology
2626:Western Electric
2619:
2612:
2605:
2596:
2582:
2581:
2572:
2571:
2562:
2561:
2552:
2551:
2550:
2423:Notable networks
2413:Wireless network
2353:Cellular network
2345:Types of network
2320:Computer network
2207:Network topology
2121:Thomas A. Watson
1976:Oliver Heaviside
1961:Philo Farnsworth
1936:Daniel Davis Jr.
1911:Charles Bourseul
1871:John Logie Baird
1580:Data compression
1575:Computer network
1527:
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1120:
1113:
1107:
1100:
1094:
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1076:
1074:
1059:Washington, D.C.
1056:
1048:
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1041:
1028:
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1005:
1004:
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397:
379:telephone keypad
335:cable television
180:telephone keypad
130:
127:
125:
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121:
119:
117:
96:
94:
89:
56:
49:
21:
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3093:
3089:
3088:
3087:
3085:
3084:
3083:
3064:
3063:
3062:
3057:
3036:Implementations
3031:
3000:
2929:
2923:
2893:
2888:
2879:Hawthorne Works
2857:
2821:
2812:Nippon Electric
2765:
2739:
2701:
2628:
2623:
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2548:
2546:
2538:
2480:
2417:
2339:
2303:
2260:
2209:
2201:
2142:
2135:
2041:Robert Metcalfe
1896:Tim Berners-Lee
1844:
1664:Information Age
1536:
1531:
1501:
1496:
1488:
1486:
1480:
1436:Disconnect tone
1402:
1397:
1319:
1311:
1280:
1275:
1267:
1265:Further reading
1262:
1261:
1252:
1248:
1239:
1235:
1221:
1211:
1205:
1204:
1200:
1189:
1188:
1184:
1179:. 6 April 2019.
1175:
1174:
1170:
1163:
1148:
1147:
1143:
1131:Don Lancaster.
1130:
1123:
1114:
1110:
1101:
1097:
1072:
1070:
1054:
1050:
1049:
1045:
1024:
1022:
1013:
1012:
1008:
1001:"TESS -- Error"
999:
998:
994:
986:
982:
973:
971:
963:
962:
958:
949:
948:
944:
927:
915:
902:
901:
897:
892:
878:
876:
853:
821:
784:
694:
693:
685:
683:
682:
681:
680:
677:
669:
666:
659:
653:
648:
633:
631:
630:
629:
620:
618:
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616:
607:
605:
604:
603:
594:
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591:
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576:
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563:
561:
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537:
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519:
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493:
491:
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480:
478:
477:
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462:
460:
459:
458:
449:
447:
446:
445:
436:
434:
433:
432:
423:
421:
420:
419:
359:
329:As a method of
221:multi-frequency
196:
188:multi-frequency
114:
92:
90:
87:
62:
42:
35:
28:
23:
22:
15:
12:
11:
5:
3092:
3090:
3082:
3081:
3076:
3066:
3065:
3059:
3058:
3056:
3055:
3050:
3045:
3039:
3037:
3033:
3032:
3030:
3029:
3024:
3019:
3014:
3008:
3006:
3002:
3001:
2999:
2998:
2993:
2988:
2983:
2978:
2973:
2968:
2963:
2958:
2953:
2948:
2943:
2937:
2935:
2934:DMTF standards
2931:
2930:
2924:
2922:
2921:
2914:
2907:
2899:
2890:
2889:
2887:
2886:
2884:Henry Dreyfuss
2881:
2876:
2871:
2865:
2863:
2859:
2858:
2856:
2855:
2850:
2845:
2840:
2835:
2829:
2827:
2823:
2822:
2820:
2819:
2814:
2809:
2804:
2799:
2794:
2789:
2784:
2779:
2773:
2771:
2767:
2766:
2764:
2763:
2758:
2753:
2747:
2745:
2741:
2740:
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2732:
2727:
2722:
2717:
2711:
2709:
2703:
2702:
2700:
2699:
2694:
2689:
2684:
2679:
2674:
2669:
2664:
2659:
2654:
2649:
2644:
2638:
2636:
2630:
2629:
2624:
2622:
2621:
2614:
2607:
2599:
2590:
2589:
2587:
2586:
2576:
2566:
2556:
2543:
2540:
2539:
2537:
2536:
2529:
2524:
2519:
2514:
2509:
2508:
2507:
2502:
2494:
2488:
2486:
2482:
2481:
2479:
2478:
2473:
2468:
2463:
2458:
2453:
2448:
2443:
2438:
2433:
2427:
2425:
2419:
2418:
2416:
2415:
2410:
2405:
2400:
2395:
2390:
2385:
2380:
2375:
2370:
2365:
2360:
2355:
2349:
2347:
2341:
2340:
2338:
2337:
2332:
2327:
2322:
2317:
2311:
2309:
2305:
2304:
2302:
2301:
2296:
2291:
2286:
2281:
2276:
2274:Space-division
2270:
2268:
2262:
2261:
2259:
2258:
2253:
2252:
2251:
2246:
2236:
2235:
2234:
2224:
2219:
2213:
2211:
2203:
2202:
2200:
2199:
2198:
2197:
2187:
2186:
2185:
2175:
2170:
2165:
2164:
2163:
2153:
2147:
2145:
2137:
2136:
2134:
2133:
2128:
2123:
2118:
2113:
2111:Camille Tissot
2108:
2103:
2098:
2093:
2088:
2086:Claude Shannon
2083:
2078:
2076:Tivadar Puskás
2073:
2068:
2063:
2058:
2053:
2048:
2046:Antonio Meucci
2043:
2038:
2033:
2028:
2023:
2018:
2016:Charles K. Kao
2013:
2008:
2003:
1998:
1993:
1991:Harold Hopkins
1988:
1983:
1978:
1973:
1968:
1963:
1958:
1953:
1948:
1943:
1938:
1933:
1928:
1923:
1918:
1913:
1908:
1903:
1898:
1893:
1891:Emile Berliner
1888:
1883:
1878:
1873:
1868:
1863:
1858:
1852:
1850:
1846:
1845:
1843:
1842:
1837:
1832:
1830:Videotelephony
1827:
1822:
1821:
1820:
1815:
1805:
1798:
1793:
1787:
1782:
1777:
1772:
1767:
1766:
1765:
1760:
1755:
1745:
1744:
1743:
1733:
1728:
1726:Radiotelephone
1723:
1718:
1713:
1708:
1703:
1698:
1693:
1692:
1691:
1681:
1676:
1671:
1666:
1661:
1656:
1651:
1646:
1641:
1636:
1631:
1630:
1629:
1624:
1619:
1614:
1612:Internet video
1604:
1603:
1602:
1597:
1592:
1587:
1577:
1572:
1567:
1562:
1557:
1552:
1546:
1544:
1538:
1537:
1532:
1530:
1529:
1522:
1515:
1507:
1498:
1497:
1485:
1482:
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1479:
1478:
1473:
1468:
1463:
1458:
1453:
1448:
1443:
1438:
1433:
1428:
1423:
1418:
1413:
1407:
1404:
1403:
1398:
1396:
1395:
1388:
1381:
1373:
1367:
1366:
1361:
1354:
1317:
1291:(1): 235–255,
1273:
1266:
1263:
1260:
1259:
1246:
1240:W. D. Reeves,
1233:
1224:|journal=
1198:
1182:
1168:
1161:
1141:
1121:
1108:
1095:
1043:
1036:DTMF cue tones
1006:
992:
980:
956:
942:
913:
894:
893:
891:
888:
887:
886:
874:
869:
864:
859:
852:
849:
820:
817:
783:
780:
726:magnetic strip
684:
678:
667:
662:
661:
660:
651:
650:
649:
647:
644:
641:
640:
627:
614:
601:
588:
584:
583:
570:
557:
544:
531:
527:
526:
513:
500:
487:
474:
470:
469:
456:
443:
430:
417:
413:
412:
409:
406:
403:
400:
358:
355:
195:
192:
132:
131:
112:
108:
107:
102:
98:
97:
84:
80:
79:
76:
72:
71:
68:
64:
63:
57:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
3091:
3080:
3077:
3075:
3072:
3071:
3069:
3054:
3051:
3049:
3046:
3044:
3041:
3040:
3038:
3034:
3028:
3025:
3023:
3020:
3018:
3015:
3013:
3010:
3009:
3007:
3003:
2997:
2996:WS-Management
2994:
2992:
2989:
2987:
2984:
2982:
2979:
2977:
2974:
2972:
2969:
2967:
2964:
2962:
2959:
2957:
2954:
2952:
2949:
2947:
2944:
2942:
2939:
2938:
2936:
2932:
2928:
2925:Standards of
2920:
2915:
2913:
2908:
2906:
2901:
2900:
2897:
2885:
2882:
2880:
2877:
2875:
2872:
2870:
2867:
2866:
2864:
2860:
2854:
2851:
2849:
2846:
2844:
2841:
2839:
2836:
2834:
2831:
2830:
2828:
2824:
2818:
2815:
2813:
2810:
2808:
2805:
2803:
2800:
2798:
2795:
2793:
2790:
2788:
2785:
2783:
2780:
2778:
2775:
2774:
2772:
2768:
2762:
2759:
2757:
2754:
2752:
2749:
2748:
2746:
2742:
2736:
2733:
2731:
2728:
2726:
2723:
2721:
2718:
2716:
2713:
2712:
2710:
2708:
2704:
2698:
2695:
2693:
2690:
2688:
2685:
2683:
2682:500/1500/2500
2680:
2678:
2675:
2673:
2670:
2668:
2665:
2663:
2660:
2658:
2655:
2653:
2650:
2648:
2645:
2643:
2640:
2639:
2637:
2635:
2631:
2627:
2620:
2615:
2613:
2608:
2606:
2601:
2600:
2597:
2585:
2577:
2575:
2567:
2565:
2557:
2555:
2545:
2544:
2541:
2534:
2530:
2528:
2525:
2523:
2520:
2518:
2515:
2513:
2510:
2506:
2503:
2501:
2498:
2497:
2495:
2493:
2490:
2489:
2487:
2483:
2477:
2474:
2472:
2469:
2467:
2464:
2462:
2459:
2457:
2454:
2452:
2449:
2447:
2444:
2442:
2439:
2437:
2434:
2432:
2429:
2428:
2426:
2424:
2420:
2414:
2411:
2409:
2406:
2404:
2401:
2399:
2396:
2394:
2391:
2389:
2386:
2384:
2381:
2379:
2376:
2374:
2371:
2369:
2366:
2364:
2361:
2359:
2356:
2354:
2351:
2350:
2348:
2346:
2342:
2336:
2333:
2331:
2328:
2326:
2323:
2321:
2318:
2316:
2313:
2312:
2310:
2306:
2300:
2299:Code-division
2297:
2295:
2292:
2290:
2287:
2285:
2284:Time-division
2282:
2280:
2277:
2275:
2272:
2271:
2269:
2267:
2263:
2257:
2254:
2250:
2247:
2245:
2242:
2241:
2240:
2237:
2233:
2230:
2229:
2228:
2225:
2223:
2220:
2218:
2215:
2214:
2212:
2210:and switching
2208:
2204:
2196:
2193:
2192:
2191:
2188:
2184:
2181:
2180:
2179:
2176:
2174:
2171:
2169:
2166:
2162:
2161:optical fiber
2159:
2158:
2157:
2154:
2152:
2151:Coaxial cable
2149:
2148:
2146:
2144:
2138:
2132:
2129:
2127:
2124:
2122:
2119:
2117:
2114:
2112:
2109:
2107:
2104:
2102:
2099:
2097:
2094:
2092:
2089:
2087:
2084:
2082:
2079:
2077:
2074:
2072:
2069:
2067:
2066:Radia Perlman
2064:
2062:
2059:
2057:
2054:
2052:
2049:
2047:
2044:
2042:
2039:
2037:
2034:
2032:
2029:
2027:
2024:
2022:
2019:
2017:
2014:
2012:
2009:
2007:
2004:
2002:
1999:
1997:
1994:
1992:
1989:
1987:
1984:
1982:
1979:
1977:
1974:
1972:
1969:
1967:
1964:
1962:
1959:
1957:
1956:Lee de Forest
1954:
1952:
1951:Thomas Edison
1949:
1947:
1944:
1942:
1941:Donald Davies
1939:
1937:
1934:
1932:
1929:
1927:
1926:Claude Chappe
1924:
1922:
1919:
1917:
1914:
1912:
1909:
1907:
1904:
1902:
1899:
1897:
1894:
1892:
1889:
1887:
1884:
1882:
1879:
1877:
1874:
1872:
1869:
1867:
1864:
1862:
1859:
1857:
1854:
1853:
1851:
1847:
1841:
1838:
1836:
1833:
1831:
1828:
1826:
1823:
1819:
1816:
1814:
1811:
1810:
1809:
1806:
1804:
1803:
1799:
1797:
1794:
1791:
1788:
1786:
1783:
1781:
1778:
1776:
1773:
1771:
1770:Smoke signals
1768:
1764:
1761:
1759:
1756:
1754:
1751:
1750:
1749:
1748:Semiconductor
1746:
1742:
1739:
1738:
1737:
1734:
1732:
1729:
1727:
1724:
1722:
1719:
1717:
1714:
1712:
1709:
1707:
1704:
1702:
1699:
1697:
1694:
1690:
1687:
1686:
1685:
1682:
1680:
1677:
1675:
1672:
1670:
1667:
1665:
1662:
1660:
1657:
1655:
1652:
1650:
1647:
1645:
1642:
1640:
1637:
1635:
1632:
1628:
1625:
1623:
1620:
1618:
1615:
1613:
1610:
1609:
1608:
1607:Digital media
1605:
1601:
1598:
1596:
1593:
1591:
1588:
1586:
1583:
1582:
1581:
1578:
1576:
1573:
1571:
1568:
1566:
1563:
1561:
1558:
1556:
1553:
1551:
1548:
1547:
1545:
1543:
1539:
1535:
1528:
1523:
1521:
1516:
1514:
1509:
1508:
1505:
1495:
1483:
1477:
1474:
1472:
1469:
1467:
1464:
1462:
1459:
1457:
1454:
1452:
1449:
1447:
1446:Off-hook tone
1444:
1442:
1439:
1437:
1434:
1432:
1429:
1427:
1424:
1422:
1419:
1417:
1414:
1412:
1409:
1408:
1405:
1401:
1394:
1389:
1387:
1382:
1380:
1375:
1374:
1371:
1365:
1362:
1359:
1356:Frank Durda,
1355:
1351:
1347:
1343:
1339:
1335:
1331:
1327:
1323:
1318:
1310:
1306:
1302:
1298:
1294:
1290:
1286:
1279:
1274:
1272:
1269:
1268:
1264:
1256:
1250:
1247:
1243:
1237:
1234:
1229:
1216:
1208:
1202:
1199:
1194:
1193:
1186:
1183:
1178:
1172:
1169:
1164:
1158:
1154:
1153:
1145:
1142:
1138:
1137:TV Typewriter
1134:
1128:
1126:
1122:
1118:
1112:
1109:
1105:
1099:
1096:
1092:
1090:
1085:
1081:
1068:
1064:
1060:
1053:
1047:
1044:
1040:
1037:
1033:
1020:
1016:
1010:
1007:
1002:
996:
993:
990:
984:
981:
970:
966:
960:
957:
952:
946:
943:
938:
932:
924:
920:
916:
914:9780137058914
910:
906:
899:
896:
889:
885:
875:
873:
870:
868:
865:
863:
860:
858:
855:
854:
850:
848:
846:
841:
839:
835:
831:
827:
818:
816:
814:
809:
805:
801:
797:
788:
781:
779:
777:
773:
769:
764:
761:
756:
754:
753:amateur radio
749:
746:
741:
738:
734:
729:
727:
723:
718:
716:
712:
707:
703:
699:
692:
690:
665:
645:
636:
623:
610:
597:
585:
579:
566:
553:
540:
528:
522:
509:
496:
483:
471:
465:
452:
439:
426:
414:
411:1633 Hz
408:1477 Hz
405:1336 Hz
402:1209 Hz
398:
392:
389:
385:
380:
371:
363:
356:
354:
352:
347:
343:
339:
336:
332:
327:
325:
321:
317:
313:
308:
306:
302:
298:
294:
290:
284:
282:
278:
273:
270:
267:
263:
260:
259:long-distance
256:
252:
248:
244:
240:
236:
232:
228:
224:
222:
218:
213:
209:
208:calling party
205:
201:
200:pulse dialing
193:
191:
189:
185:
181:
176:
174:
170:
166:
162:
158:
154:
150:
146:
142:
138:
129:
113:
109:
106:
103:
99:
85:
81:
77:
73:
69:
65:
60:
55:
50:
44:
40:
33:
19:
2715:Panel switch
2266:Multiplexing
2141:Transmission
2106:Nikola Tesla
2096:Henry Sutton
2051:Samuel Morse
1981:Robert Hooke
1946:Amos Dolbear
1881:John Bardeen
1800:
1780:Telautograph
1684:Mobile phone
1639:Edholm's law
1622:social media
1555:Broadcasting
1431:Reorder tone
1421:Ringing tone
1329:
1325:
1288:
1284:
1254:
1249:
1241:
1236:
1215:cite journal
1201:
1191:
1185:
1171:
1151:
1144:
1116:
1111:
1103:
1098:
1079:
1078:
1071:. Retrieved
1069:. FCC 94-288
1046:
1035:
1031:
1030:
1023:. Retrieved
1009:
995:
988:
983:
972:. Retrieved
968:
959:
945:
904:
898:
842:
822:
812:
796:filter banks
793:
765:
757:
750:
744:
742:
730:
719:
695:
664:DTMF dialing
587:941 Hz
530:852 Hz
473:770 Hz
416:697 Hz
383:
376:
351:IP telephony
338:broadcasters
328:
319:
315:
312:tone dialing
311:
309:
296:
285:
280:
276:
274:
230:
226:
225:
197:
184:rotary dials
177:
172:
160:
140:
136:
135:
83:Year started
67:Abbreviation
43:
2826:Competitors
2792:Bell System
2642:Candlestick
2466:NPL network
2178:Radio waves
2116:Alfred Vail
2026:Hedy Lamarr
2011:Dawon Kahng
1971:Elisha Gray
1931:Yogen Dalal
1856:Nasir Ahmed
1790:Teleprinter
1654:Heliographs
1426:Busy signal
843:Some early
698:number sign
326:in Canada.
247:Bell System
223:signaling.
212:rotary dial
163:for use in
157:Bell System
3068:Categories
2761:Touch-Tone
2634:Telephones
2512:Antarctica
2471:Toasternet
2393:Television
1876:Paul Baran
1808:Television
1792:(teletype)
1785:Telegraphy
1763:transistor
1741:Phryctoria
1711:Photophone
1689:Smartphone
1679:Mass media
1253:AT&T,
987:AT&T,
974:2024-05-23
969:Networking
890:References
774:modulated
702:octothorpe
689:media help
297:Touch-Tone
264:used a 16-
204:local loop
161:Touch-Tone
18:Touch-tone
2787:Bell Labs
2751:Vitaphone
2496:Americas
2485:Locations
2456:Internet2
2217:Bandwidth
1921:Vint Cerf
1818:streaming
1796:Telephone
1736:Semaphore
1627:streaming
1411:Dial tone
1350:265354535
1305:0005-8580
1032:Cue Tones
931:cite book
923:779863446
840:devices.
832:. Bell's
768:caller ID
722:payphones
715:caller ID
377:The DTMF
342:cue tones
243:protocols
239:sine wave
235:pure tone
149:telephone
101:Committee
39:TouchTone
2862:See also
2692:Trimline
2687:Princess
2564:Category
2451:Internet
2441:CYCLADES
2358:Ethernet
2308:Concepts
2232:terminal
2183:wireless
2006:Bob Kahn
1849:Pioneers
1674:Internet
1565:Cable TV
1451:Zip tone
1416:Ringtone
1309:archived
1073:26 April
1025:26 April
872:Cue tone
851:See also
838:blue box
782:Decoding
772:Bell 202
706:asterisk
320:Digitone
124:/T-REC-Q
2976:Redfish
2848:Kellogg
2797:Graybar
2584:Commons
2574:Outline
2527:Oceania
2446:FidoNet
2431:ARPANET
2244:circuit
1813:digital
1542:History
1456:2600 Hz
1360:, 2006.
1336:–1012.
733:AUTOVON
720:Public
255:in-band
143:) is a
111:Website
91: (
59:Autovon
3017:JSR-48
2986:SMBIOS
2522:Europe
2492:Africa
2476:Usenet
2436:BITNET
2373:Mobile
2249:packet
1758:MOSFET
1753:device
1550:Beacon
1348:
1303:
1257:, 1968
1159:
921:
911:
845:modems
357:Keypad
269:keypad
237:(pure
78:Active
75:Status
3027:SMI-S
2981:SMASH
2971:NC-SI
2505:South
2500:North
2461:JANET
2398:Telex
2388:Radio
2227:Nodes
2222:Links
2143:media
1721:Radio
1706:Pager
1634:Drums
1600:video
1595:image
1585:audio
1346:S2CID
1332:(4):
1312:(PDF)
1281:(PDF)
1055:(PDF)
813:twist
621:#
595:*
305:ITU-T
266:digit
251:CCITT
169:ITU-T
105:ITU-T
3012:CMPI
2991:WBEM
2961:DASH
2956:CIMI
2927:DMTF
2802:IBTC
2735:5ESS
2730:1ESS
2677:5302
2517:Asia
2403:UUCP
2363:ISDN
1301:ISSN
1228:help
1157:ISBN
1075:2020
1027:2020
937:link
919:OCLC
909:ISBN
731:The
316:DTMF
279:and
249:and
141:DTMF
122:/rec
120:.int
118:.itu
93:1963
86:1963
70:DTMF
3053:WQL
3048:OMI
3043:WMI
3022:OVF
2966:DMI
2951:CIM
2946:CDM
2941:ASF
2843:ITT
2838:GTE
2725:5XB
2720:1XB
2672:302
2667:202
2662:102
2408:WAN
2378:NGN
2368:LAN
1649:Fax
1590:DCT
1338:doi
1334:995
1293:doi
1135:. (
1089:NWS
1084:EAS
815:).
760:VHS
340:as
314:or
293:SS7
173:MF4
128:/en
126:.23
116:www
3070::
2657:D1
2652:B1
2647:A1
1344:.
1330:39
1328:.
1324:.
1307:,
1299:,
1289:39
1287:,
1283:,
1219::
1217:}}
1213:{{
1124:^
1077:.
1067:23
1061::
1057:.
1029:.
1017:.
967:.
933:}}
929:{{
917:.
728:.
717:.
388:Hz
289:R2
231:MF
175:.
2918:e
2911:t
2904:v
2618:e
2611:t
2604:v
2535:)
2531:(
1526:e
1519:t
1512:v
1392:e
1385:t
1378:v
1352:.
1340::
1316:.
1295::
1230:)
1226:(
1209:.
1165:.
1003:.
977:.
939:)
925:.
745:A
691:.
634:D
608:0
577:C
564:9
551:8
538:7
520:B
507:6
494:5
481:4
463:A
450:3
437:2
424:1
384:1
281:*
277:#
229:(
139:(
95:)
41:.
34:.
20:)
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