1312:
25:
454:. The frequencies may not vary more than ±1.8% from their nominal frequency, or the switching center will ignore the signal. The high frequencies may be the same volume as – or louder than – the low frequencies when sent across the line. The loudness difference between the high and low frequencies can be as large as 3
351:
The use of signalling protocols rather than audible tones means that a voice channel to the distant switch is unnecessary unless a call is connected. This saves network bandwidth, switch capacity and is often more user friendly as it can provide local tones or even on-screen feedback to end users.
343:
on a foreign network will often be provided with a ringback tone from the network they are temporarily hosted on. For example, calling a US phone in Europe may return a
European ringback tone or vice versa. Increasingly, networks may opt to play their own domestic tones instead, making roaming
445:
products will not cause an unreliable signal. 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. The frequencies were initially designed with a
320:
Outside of Europe and North
America, tone plans vary from country to country but are usually similar enough to be easily recognised by end users calling from abroad and by automatic dialling equipment, such as fax machines and modems.
304:
National telephone systems define tones to indicate the status of lines, equipment, or the result of calls with special tones. Such tones are generally standardized in each country, and may consist of single or multiple frequencies.
347:
In some instances, the tones are entirely generated by the local network or even by the telephone itself; this is increasingly common on VoIP-based services. In this case no distantly generated tones will be heard.
1150:"Access and Terminals (AT); Public Switched Telephone Network; Support of legacy terminals by BroadBand IP equipment; Listing of the most relevant features and functionalities; Part 2: Analogue PSTN terminals"
324:
Many countries have adopted plans similar to those recommended by the ETSI, others have influences from North
American or British standards, while some like Japan and Australia are unique to those countries.
316:
The most notable exceptions are found in the U.K. (distinct system of tones see table below), Ireland (British style ringback tone), Italy (non continuous dial tone) and France (tone frequencies at 440Hz).
308:
Most
European countries have harmonised to a system of tones based on a single 425 Hz, while the United States uses a dual-frequency system. Exceptions exist, notably in private networks and on some
1138:
Transmitted signaling rate of 93 ms per digit with minimum 40 ms pause between tones. A 40 ms tone should be detected and a 23 ms tone must be rejected.
171:
313:(VoIP) equipment. In Europe, some countries maintain national exceptions based on established older standards and have not fully adopted ETSI recommendations.
328:
In many cases, when calling from abroad, busy, reorder and other call failure tones may be played by the local switch. Modern signalling protocols like
1278:
42:
1208:
108:
336:
or announcement generated by a distant switch in a foreign network will ever be heard by callers from other countries or networks.
1149:
89:
61:
1217:
46:
170:
is a tone description format that may be used to specify the tone. Many
European systems follow the recommendations of the
68:
344:
seamless. In this case the ringing state is sent by the host network and the tone is generated by the home network.
75:
1335:
35:
1283:
282:
1258:
897:
600:
275:
57:
1298:
1293:
859:
555:
438:
376:
329:
134:
1288:
1201:
1137:
249:
923:
166:
recommendations define the technical characteristics and intended usage of some of these tones.
82:
1316:
434:
458:(dB) and is referred to as "twist." The duration of the tone should be at least 537 ms.
1194:
232:
163:
159:
1253:
1181:
442:
217:
207:
198:
223:
130:
1329:
1263:
740:
404:
333:
310:
138:
1248:
1238:
878:
626:
578:
533:
292:
259:
254:
193:
1186:
1182:
Various Tones Used in
National Networks (According to ITU-T Recommendation E.180)
1243:
187:
145:
24:
1273:
451:
167:
1228:
911:
Fq 1 On 0.33s, Off 0.33s, Fq 2 On 0.33s, Off 0.33s, Fq 3 On 0.33s, Off 1.0s
840:
789:
614:
Fq 1 On 0.33s, Off 0.33s, Fq 2 On 0.33s, Off 0.33s, Fq 3 On 0.33s, Off 1.0s
491:
390:
212:
183:
122:
152:
are designed to recognize certain tones, such as dial tone and busy tone.
1268:
1233:
622:
418:
288:
264:
455:
340:
447:
156:
149:
129:
are audible tones that provide an indication of the status of a
1190:
133:
to the user. The tones are generated by a central office or a
18:
1107:
1.0 s on, 15 s off (1st), 0.36 s on, 15 s off (subsequent)
922:
Supervisory tones in the
Australian PSTN are defined in
755:
Fq 1 & Fq 2 On 0.4s, off 0.2, On 0.4s, Off 2.0s
49:. Unsourced material may be challenged and removed.
172:European Telecommunications Standards Institute
1159:. ETSI TR 101 973-2 V1.1.1 (2002–12): 10 to 31
1202:
332:send this information digitally; thus only a
8:
926:, published by the Communications Alliance.
1209:
1195:
1187:
1096:0.2 s on, 0.2 s off, 0.2 s on, 4.4 s off
694:EU national exceptions to harmonised ETSI
109:Learn how and when to remove this message
1064:
928:
817:
807:No and no plans to harmonise announced.
758:No and no plans to harmonise announced.
708:
465:
450:of 21/19, which is slightly less than a
433:The tone frequencies, as defined by the
359:
1130:
1037:0.4 s on, 0.2 s off, 0.4 s on, 2 s off
1026:0.4 s on, 0.2 s off, 0.4 s on, 2 s off
1015:0.4 s on, 0.2 s off, 0.4 s on, 2 s off
1004:0.4 s on, 0.2 s off, 0.4 s on, 2 s off
664:On 0.20s, Off 0.20s repeated 3 times
7:
1001:425 Hz, amplitude modulated by 25 Hz
957:425 Hz, amplitude modulated by 25 Hz
892:On 0.4s, off 0.2, On 0.4s, Off 2.0s
144:Telecommunication equipment such as
47:adding citations to reliable sources
804:On 0.2s, Off 0.2s, On 0.6s, Off 1s
684:On 0.25s, Off 0.25s (not repeated)
14:
781:No, but harmonisation announced.
641:On 0.2, Off 0.2, On 0.2, Off 9.0
222:End of three-party service tone (
1310:
23:
300:Regional and national standards
34:needs additional citations for
1218:Signaling (telecommunications)
898:Special information tone (SIT)
601:Special information tone (SIT)
1:
1085:0.425 s burst, 15 s interval
281:Stutter dial tone (used as a
260:Ringing tone, audible ringing
910:
907:
904:
901:
891:
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885:
882:
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869:
866:
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844:
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797:
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568:
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549:
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543:
540:
537:
527:
524:
521:
518:
515:
513:Special / stutter dial tone
507:
504:
501:
498:
495:
426:
423:
412:
409:
398:
395:
384:
381:
1104:425 Hz or 525 Hz or 1400 Hz
1352:
1307:
1284:Multi-frequency signaling
1279:Dual-tone multi-frequency
1224:
651:Radio path not available
437:, are selected such that
283:message-waiting indicator
1259:Special information tone
1112:Number unobtainable tone
1053:Number unobtainable tone
1048:0.375 s on, 0.375 s off
1023:400 Hz + 425 Hz + 450 Hz
968:400 Hz + 425 Hz + 450 Hz
649:Call dropped (GSM/3GPP)
276:Special information tone
265:Ring tone, power ringing
1299:Signalling System No. 7
1294:Signalling System No. 6
229:Executive override tone
135:private branch exchange
1289:Signaling System No. 5
766:All tones – frequency
1317:Telephones portal
1157:ETSI Technical Report
250:Recorder warning tone
1118:2.5 s on, 0.5 s off
1071:Frequency definition
1059:2.5 s on, 0.5 s off
935:Frequency definition
873:On 0.75s, Off 0.75s
462:ETSI guidelines (EU)
356:North American tones
58:"Call-progress tone"
43:improve this article
819:
710:
525:On 0.5s, Off 0.05s
467:
361:
127:call progress tones
818:
709:
592:On 0.25, Off 0.25
569:On 0.5s, Off 0.5s
466:
360:
1336:Telephony signals
1323:
1322:
1122:
1121:
1068:Post-answer tones
1063:
1062:
915:
914:
811:
810:
691:
690:
435:precise tone plan
431:
430:
272:Special dial tone
224:three-way calling
204:Confirmation tone
119:
118:
111:
93:
1343:
1315:
1314:
1313:
1211:
1204:
1197:
1188:
1169:
1168:
1166:
1164:
1154:
1146:
1140:
1135:
1093:425 Hz or 525 Hz
1065:
932:Pre-answer tones
929:
918:Australian tones
820:
732:ETSI harmonised
711:
706:
705:
701:
547:On 1.0s, Off 4s
486:ETSI Harmonised
468:
362:
269:Second dial tone
243:Recall dial tone
114:
107:
103:
100:
94:
92:
51:
27:
19:
16:Telephony signal
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1350:
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1325:
1324:
1319:
1311:
1309:
1303:
1254:Disconnect tone
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1215:
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1173:
1172:
1162:
1160:
1152:
1148:
1147:
1143:
1136:
1132:
1127:
1034:413 Hz + 438 Hz
1031:Ringback tone D
1020:Ringback tone C
1012:400 Hz + 450 Hz
1009:Ringback tone B
998:Ringback tone A
990:413 Hz + 438 Hz
979:400 Hz + 425 Hz
920:
816:
707:
703:
699:
697:
696:
464:
443:intermodulation
371:High frequency
358:
302:
237:Preemption tone
218:Disconnect tone
208:Congestion tone
199:Conference call
180:
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104:
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52:
50:
40:
28:
17:
12:
11:
5:
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1176:External links
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577:Congestion or
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397:
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368:Low frequency
366:
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339:Mobile phones
301:
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131:telephone call
117:
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13:
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3:
2:
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1264:Off-hook tone
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1103:
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1074:Tone cadence
1073:
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1058:
1055:
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1007:
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1000:
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992:
989:
986:
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964:
963:
959:
956:
953:
952:
948:
945:
942:
941:
938:Tone cadence
937:
934:
931:
930:
927:
925:
917:
908:1800 Hz
905:1400 Hz
899:
896:
895:
880:
877:
876:
861:
858:
857:
842:
839:
838:
834:
831:
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821:
813:
791:
788:
785:
784:
765:
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761:
742:
739:
736:
735:
731:
728:
725:
722:
719:
716:
713:
712:
702:
693:
672:Release tone
671:
670:
652:
648:
647:
628:
624:
621:
620:
611:1800 Hz
608:1400 Hz
602:
599:
598:
580:
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575:
557:
554:
553:
535:
532:
531:
512:
511:
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363:
355:
353:
349:
345:
342:
337:
335:
334:ringback tone
331:
326:
322:
318:
314:
312:
311:voice over IP
306:
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139:calling party
137:(PBX) to the
136:
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113:
110:
102:
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
1249:Reorder tone
1239:Ringing tone
1161:. Retrieved
1156:
1144:
1133:
1090:Call waiting
921:
902:950 Hz
886:450 Hz
883:400 Hz
879:Ringing tone
864:400 Hz
845:350 Hz
795:425 Hz
769:440 Hz
749:450 Hz
746:400 Hz
741:Ringing tone
675:425 Hz
655:425 Hz
650:
632:425 Hz
627:call waiting
605:950 Hz
583:425 Hz
579:reorder tone
560:425 Hz
538:425 Hz
534:Ringing tone
516:425 Hz
496:425 Hz
432:
424:440 Hz
413:480 Hz
410:440 Hz
405:Ringing tone
399:440 Hz
396:350 Hz
385:620 Hz
382:480 Hz
350:
346:
338:
327:
323:
319:
315:
307:
303:
293:Call waiting
255:Reorder tone
233:Holding tone
194:Comfort tone
154:
146:fax machines
143:
126:
120:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
1244:Busy signal
993:continuous
987:Dial tone E
982:continuous
976:Dial tone D
971:continuous
965:Dial tone C
960:continuous
954:Dial tone B
949:continuous
943:Dial tone A
860:Busy signal
854:Continuous
556:Busy signal
505:Continuous
377:Busy signal
246:Record tone
188:busy signal
99:August 2024
1125:References
1101:Conference
924:AS/CA S002
792:– cadence
717:Exception
452:whole tone
240:Queue tone
168:ToneScript
69:newspapers
1229:Dial tone
1079:Recording
1042:Busy tone
841:Dial tone
790:Dial tone
492:Dial tone
439:harmonics
391:Dial tone
213:Dial tone
184:Busy tone
123:telephony
1330:Category
1269:Zip tone
1234:Ringtone
1163:18 April
835:Cadence
814:UK tones
743:UK tone
737:Ireland
729:Cadence
714:Country
623:Zip tone
483:Cadence
456:decibels
419:Zip tone
289:Zip tone
174:(ETSI).
1274:2600 Hz
1082:1400 Hz
848:450 Hz
763:France
341:roaming
83:scholar
1115:425 Hz
1056:425 Hz
1045:425 Hz
946:425 Hz
823:Event
786:Italy
698:": -->
471:Event
365:Event
150:modems
85:
78:
71:
64:
56:
1153:(PDF)
889:----
870:----
867:----
851:----
832:Fq 3
829:Fq 2
826:Fq 1
801:----
798:----
778:----
775:----
772:----
752:----
726:Fq 3
723:Fq 2
720:Fq 1
681:----
678:----
661:----
658:----
638:----
635:----
589:----
586:----
566:----
563:----
544:----
541:----
522:----
519:----
502:----
499:----
480:Fq 3
477:Fq 2
474:Fq 1
448:ratio
421:(US)
407:(US)
393:(US)
379:(US)
295:tone)
278:(SIT)
178:Types
164:E.182
160:E.180
157:ITU-T
90:JSTOR
76:books
1165:2021
700:edit
687:Yes
667:Yes
644:Yes
617:Yes
595:Yes
572:Yes
550:Yes
528:Yes
508:Yes
441:and
291:(or
201:tone
186:(or
162:and
155:The
148:and
62:news
330:SS7
121:In
45:by
1332::
1155:.
629:)
427:-
141:.
125:,
1210:e
1203:t
1196:v
1167:.
704:]
625:(
285:)
226:)
190:)
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
