1323:
36:
465:. 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
362:
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.
354:
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
456:
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
331:
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.
315:
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.
358:
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.
1161:"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"
335:
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.
327:
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).
319:
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
1149:
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.
182:
324:(VoIP) equipment. In Europe, some countries maintain national exceptions based on established older standards and have not fully adopted ETSI recommendations.
339:
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
1289:
53:
1219:
119:
347:
or announcement generated by a distant switch in a foreign network will ever be heard by callers from other countries or networks.
1160:
100:
72:
1228:
57:
181:
is a tone description format that may be used to specify the tone. Many
European systems follow the recommendations of the
79:
355:
seamless. In this case the ringing state is sent by the host network and the tone is generated by the home network.
86:
1346:
46:
1294:
293:
1269:
908:
611:
286:
68:
1309:
1304:
870:
566:
449:
387:
340:
145:
1299:
1212:
1148:
260:
934:
177:
recommendations define the technical characteristics and intended usage of some of these tones.
93:
1327:
445:
469:(dB) and is referred to as "twist." The duration of the tone should be at least 537 ms.
1205:
243:
174:
170:
1264:
1192:
453:
228:
218:
209:
234:
141:
1340:
1274:
751:
415:
344:
321:
149:
1259:
1249:
889:
637:
589:
544:
303:
270:
265:
204:
17:
1197:
1193:
Various Tones Used in
National Networks (According to ITU-T Recommendation E.180)
1254:
198:
156:
35:
1284:
462:
178:
1239:
922:
Fq 1 On 0.33s, Off 0.33s, Fq 2 On 0.33s, Off 0.33s, Fq 3 On 0.33s, Off 1.0s
851:
800:
625:
Fq 1 On 0.33s, Off 0.33s, Fq 2 On 0.33s, Off 0.33s, Fq 3 On 0.33s, Off 1.0s
502:
401:
223:
194:
133:
163:
are designed to recognize certain tones, such as dial tone and busy tone.
1279:
1244:
633:
429:
299:
275:
466:
351:
458:
167:
160:
140:
are audible tones that provide an indication of the status of a
1201:
144:
to the user. The tones are generated by a central office or a
29:
1118:
1.0 s on, 15 s off (1st), 0.36 s on, 15 s off (subsequent)
933:
Supervisory tones in the
Australian PSTN are defined in
766:
Fq 1 & Fq 2 On 0.4s, off 0.2, On 0.4s, Off 2.0s
60:. Unsourced material may be challenged and removed.
183:European Telecommunications Standards Institute
1170:. ETSI TR 101 973-2 V1.1.1 (2002–12): 10 to 31
1213:
343:send this information digitally; thus only a
8:
937:, published by the Communications Alliance.
1220:
1206:
1198:
1107:0.2 s on, 0.2 s off, 0.2 s on, 4.4 s off
705:EU national exceptions to harmonised ETSI
120:Learn how and when to remove this message
1075:
939:
828:
818:No and no plans to harmonise announced.
769:No and no plans to harmonise announced.
719:
476:
461:of 21/19, which is slightly less than a
444:The tone frequencies, as defined by the
370:
1141:
1048:0.4 s on, 0.2 s off, 0.4 s on, 2 s off
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
675:On 0.20s, Off 0.20s repeated 3 times
7:
1012:425 Hz, amplitude modulated by 25 Hz
968:425 Hz, amplitude modulated by 25 Hz
903:On 0.4s, off 0.2, On 0.4s, Off 2.0s
155:Telecommunication equipment such as
58:adding citations to reliable sources
815:On 0.2s, Off 0.2s, On 0.6s, Off 1s
695:On 0.25s, Off 0.25s (not repeated)
25:
792:No, but harmonisation announced.
652:On 0.2, Off 0.2, On 0.2, Off 9.0
233:End of three-party service tone (
1321:
34:
311:Regional and national standards
45:needs additional citations for
1229:Signaling (telecommunications)
909:Special information tone (SIT)
612:Special information tone (SIT)
1:
1096:0.425 s burst, 15 s interval
292:Stutter dial tone (used as a
271:Ringing tone, audible ringing
921:
918:
915:
912:
902:
899:
896:
893:
883:
880:
877:
874:
864:
861:
858:
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817:
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811:
808:
805:
791:
788:
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779:
768:
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582:
579:
576:
573:
570:
560:
557:
554:
551:
548:
538:
535:
532:
529:
526:
524:Special / stutter dial tone
518:
515:
512:
509:
506:
437:
434:
423:
420:
409:
406:
395:
392:
1115:425 Hz or 525 Hz or 1400 Hz
1363:
1318:
1295:Multi-frequency signaling
1290:Dual-tone multi-frequency
1235:
662:Radio path not available
448:, are selected such that
294:message-waiting indicator
1270:Special information tone
1123:Number unobtainable tone
1064:Number unobtainable tone
1059:0.375 s on, 0.375 s off
1034:400 Hz + 425 Hz + 450 Hz
979:400 Hz + 425 Hz + 450 Hz
660:Call dropped (GSM/3GPP)
287:Special information tone
276:Ring tone, power ringing
1310:Signalling System No. 7
1305:Signalling System No. 6
240:Executive override tone
146:private branch exchange
1300:Signaling System No. 5
777:All tones – frequency
1328:Telephones portal
1168:ETSI Technical Report
261:Recorder warning tone
1129:2.5 s on, 0.5 s off
1082:Frequency definition
1070:2.5 s on, 0.5 s off
946:Frequency definition
884:On 0.75s, Off 0.75s
473:ETSI guidelines (EU)
367:North American tones
69:"Call-progress tone"
54:improve this article
830:
721:
536:On 0.5s, Off 0.05s
478:
372:
138:call progress tones
829:
720:
603:On 0.25, Off 0.25
580:On 0.5s, Off 0.5s
477:
371:
18:Call progress tone
1347:Telephony signals
1334:
1333:
1133:
1132:
1079:Post-answer tones
1074:
1073:
926:
925:
822:
821:
702:
701:
446:precise tone plan
442:
441:
283:Special dial tone
235:three-way calling
215:Confirmation tone
130:
129:
122:
104:
16:(Redirected from
1354:
1326:
1325:
1324:
1222:
1215:
1208:
1199:
1180:
1179:
1177:
1175:
1165:
1157:
1151:
1146:
1104:425 Hz or 525 Hz
1076:
943:Pre-answer tones
940:
929:Australian tones
831:
743:ETSI harmonised
722:
717:
716:
712:
558:On 1.0s, Off 4s
497:ETSI Harmonised
479:
373:
280:Second dial tone
254:Recall dial tone
125:
118:
114:
111:
105:
103:
62:
38:
30:
27:Telephony signal
21:
1362:
1361:
1357:
1356:
1355:
1353:
1352:
1351:
1337:
1336:
1335:
1330:
1322:
1320:
1314:
1265:Disconnect tone
1231:
1226:
1189:
1184:
1183:
1173:
1171:
1163:
1159:
1158:
1154:
1147:
1143:
1138:
1045:413 Hz + 438 Hz
1042:Ringback tone D
1031:Ringback tone C
1023:400 Hz + 450 Hz
1020:Ringback tone B
1009:Ringback tone A
1001:413 Hz + 438 Hz
990:400 Hz + 425 Hz
931:
827:
718:
714:
710:
708:
707:
475:
454:intermodulation
382:High frequency
369:
313:
248:Preemption tone
229:Disconnect tone
219:Congestion tone
210:Conference call
191:
126:
115:
109:
106:
63:
61:
51:
39:
28:
23:
22:
15:
12:
11:
5:
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1187:External links
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1024:
1021:
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745:
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738:
735:
732:
729:
726:
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703:
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629:
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623:
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608:
607:
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601:
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588:Congestion or
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572:
569:
563:
562:
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553:
550:
547:
541:
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531:
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525:
521:
520:
517:
514:
511:
508:
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489:
486:
483:
474:
471:
440:
439:
436:
433:
426:
425:
422:
419:
412:
411:
408:
405:
398:
397:
394:
391:
384:
383:
380:
379:Low frequency
377:
368:
365:
350:Mobile phones
312:
309:
308:
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297:
290:
284:
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278:
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190:
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142:telephone call
128:
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42:
40:
33:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
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1275:Off-hook tone
1273:
1271:
1268:
1266:
1263:
1261:
1258:
1256:
1253:
1251:
1248:
1246:
1243:
1241:
1238:
1237:
1234:
1230:
1223:
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1211:
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1204:
1203:
1200:
1194:
1191:
1190:
1186:
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1156:
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1142:
1135:
1128:
1125:
1122:
1121:
1117:
1114:
1111:
1110:
1106:
1103:
1100:
1099:
1095:
1092:
1089:
1088:
1085:Tone cadence
1084:
1081:
1078:
1077:
1069:
1066:
1063:
1062:
1058:
1055:
1052:
1051:
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1033:
1030:
1029:
1025:
1022:
1019:
1018:
1014:
1011:
1008:
1007:
1003:
1000:
997:
996:
992:
989:
986:
985:
981:
978:
975:
974:
970:
967:
964:
963:
959:
956:
953:
952:
949:Tone cadence
948:
945:
942:
941:
938:
936:
928:
919:1800 Hz
916:1400 Hz
910:
907:
906:
891:
888:
887:
872:
869:
868:
853:
850:
849:
845:
842:
839:
836:
833:
832:
824:
802:
799:
796:
795:
776:
773:
772:
753:
750:
747:
746:
742:
739:
736:
733:
730:
727:
724:
723:
713:
704:
683:Release tone
682:
681:
663:
659:
658:
639:
635:
632:
631:
622:1800 Hz
619:1400 Hz
613:
610:
609:
591:
587:
586:
568:
565:
564:
546:
543:
542:
523:
522:
504:
501:
500:
496:
493:
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487:
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464:
460:
455:
451:
447:
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428:
427:
417:
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403:
400:
399:
389:
386:
385:
381:
378:
375:
374:
366:
364:
360:
356:
353:
348:
346:
345:ringback tone
342:
337:
333:
329:
325:
323:
322:voice over IP
317:
310:
305:
301:
298:
295:
291:
288:
285:
282:
279:
277:
274:
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269:
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239:
236:
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196:
193:
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188:
186:
184:
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158:
153:
151:
150:calling party
148:(PBX) to the
147:
143:
139:
135:
124:
121:
113:
102:
99:
95:
92:
88:
85:
81:
78:
74:
71: –
70:
66:
65:Find sources:
59:
55:
49:
48:
43:This article
41:
37:
32:
31:
19:
1260:Reorder tone
1250:Ringing tone
1172:. Retrieved
1167:
1155:
1144:
1101:Call waiting
932:
913:950 Hz
897:450 Hz
894:400 Hz
890:Ringing tone
875:400 Hz
856:350 Hz
806:425 Hz
780:440 Hz
760:450 Hz
757:400 Hz
752:Ringing tone
686:425 Hz
666:425 Hz
661:
643:425 Hz
638:call waiting
616:950 Hz
594:425 Hz
590:reorder tone
571:425 Hz
549:425 Hz
545:Ringing tone
527:425 Hz
507:425 Hz
443:
435:440 Hz
424:480 Hz
421:440 Hz
416:Ringing tone
410:440 Hz
407:350 Hz
396:620 Hz
393:480 Hz
361:
357:
349:
338:
334:
330:
326:
318:
314:
304:Call waiting
266:Reorder tone
244:Holding tone
205:Comfort tone
165:
157:fax machines
154:
137:
131:
116:
107:
97:
90:
83:
76:
64:
52:Please help
47:verification
44:
1255:Busy signal
1004:continuous
998:Dial tone E
993:continuous
987:Dial tone D
982:continuous
976:Dial tone C
971:continuous
965:Dial tone B
960:continuous
954:Dial tone A
871:Busy signal
865:Continuous
567:Busy signal
516:Continuous
388:Busy signal
257:Record tone
199:busy signal
110:August 2024
1136:References
1112:Conference
935:AS/CA S002
803:– cadence
728:Exception
463:whole tone
251:Queue tone
179:ToneScript
80:newspapers
1240:Dial tone
1090:Recording
1053:Busy tone
852:Dial tone
801:Dial tone
503:Dial tone
450:harmonics
402:Dial tone
224:Dial tone
195:Busy tone
134:telephony
1341:Category
1280:Zip tone
1245:Ringtone
1174:18 April
846:Cadence
825:UK tones
754:UK tone
748:Ireland
740:Cadence
725:Country
634:Zip tone
494:Cadence
467:decibels
430:Zip tone
300:Zip tone
185:(ETSI).
1285:2600 Hz
1093:1400 Hz
859:450 Hz
774:France
352:roaming
94:scholar
1126:425 Hz
1067:425 Hz
1056:425 Hz
957:425 Hz
834:Event
797:Italy
709:": -->
482:Event
376:Event
161:modems
96:
89:
82:
75:
67:
1164:(PDF)
900:----
881:----
878:----
862:----
843:Fq 3
840:Fq 2
837:Fq 1
812:----
809:----
789:----
786:----
783:----
763:----
737:Fq 3
734:Fq 2
731:Fq 1
692:----
689:----
672:----
669:----
649:----
646:----
600:----
597:----
577:----
574:----
555:----
552:----
533:----
530:----
513:----
510:----
491:Fq 3
488:Fq 2
485:Fq 1
459:ratio
432:(US)
418:(US)
404:(US)
390:(US)
306:tone)
289:(SIT)
189:Types
175:E.182
171:E.180
168:ITU-T
101:JSTOR
87:books
1176:2021
711:edit
698:Yes
678:Yes
655:Yes
628:Yes
606:Yes
583:Yes
561:Yes
539:Yes
519:Yes
452:and
302:(or
212:tone
197:(or
173:and
166:The
159:and
73:news
341:SS7
132:In
56:by
1343::
1166:.
640:)
438:-
152:.
136:,
1221:e
1214:t
1207:v
1178:.
715:]
636:(
296:)
237:)
201:)
123:)
117:(
112:)
108:(
98:·
91:·
84:·
77:·
50:.
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
