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at 1200 baud (Mode 2), (or at a "fallback rate" of 600 baud, mode 1) for the forward data-transmission channel, and an optional 75 baud backward channel.
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applications where the backward channel was used to send keyboard data in an asymmetrical full duplex scheme in devices such as the
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The 75 baud backward channel was originally envisioned for use in error correction schemes, but V.23 was also widely used in
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countries, (and perhaps elsewhere), V.23 Mode 2 AFSK modulation, (without the backward channel) is used to transmit
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ITU-T Recommendation V.23: 600/1200-Baud Modem
Standardized for Use in the General Switched Telephone Network
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communications standard defines a similar modulation scheme.
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V.23 backward channel AFSK uses a 390 Hz tone (F
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49:. Unsourced material may be challenged and removed.
977:Telecommunications-related introductions in 1988
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183:V.23 Mode 2 AFSK uses a 1300 Hz tone (F
152:V.23 Mode 1 AFSK uses a 1300 Hz tone (F
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207:), and a 1700 Hz center frequency (F
176:), and a 1500 Hz center frequency (F
109:Learn how and when to remove this message
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415:List of ITU-T V-series recommendations
370:
272:
905:
47:adding citations to reliable sources
18:
13:
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895:All articles beginning with "ITU"
669:G.9700, G.9701, G.9710 and G.9711
355:
345:"Sync Async Lease line V23 Modem"
909:
23:
34:needs additional citations for
982:ITU-T V Series Recommendations
434:Category:ITU-T recommendations
429:Category:ITU-R recommendations
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317:(v0.39 ed.), January 2007
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1:
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925:. You can help Knowledge by
311:"Appendix G: Antique Modems"
138:audio frequency-shift keying
7:
400:recommendations (standards)
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129:standard first approved by
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362:the ITU V.23 normalization
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840:ITU-R 468 noise weighting
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133:precursor CCITT in 1964.
917:This article related to
420:List of ITU letter codes
256:public telephone network
333:, ITU, 1993, p. 1
226:) and a 450 Hz (F
125:standard was an early
195:) and 2100 Hz (F
164:) and 1700 Hz (F
234:(typically a binary
222:(typically a binary
203:(typically a binary
191:(typically a binary
172:(typically a binary
160:(typically a binary
43:improve this article
740:H.262/MPEG-2 Video
273:Related technology
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250:information over
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775:H.323 Gatekeeper
760:H.266/MPEG-I VVC
750:H.264/MPEG-4 AVC
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443:G series (ITU-T)
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54:Find sources:
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32:This article
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927:expanding it
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870:ITU-R BT.709
865:ITU-R BT.601
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58:"ITU-T V.23"
53:
41:Please help
36:verification
33:
425:Categories:
315:Modem-HOWTO
146:full-duplex
966:Categories
297:References
252:POTS lines
69:newspapers
919:telephony
891:See also:
291:Caller ID
248:Caller ID
99:July 2022
795:V series
285:See also
279:BELL 202
263:Videotex
244:European
242:In some
797:(ITU-T)
705:H.225.0
700:H.222.0
644:G.993.2
639:G.993.1
632:Annex M
627:G.992.5
622:G.992.4
615:Annex L
610:Annex J
605:G.992.3
600:G.992.2
595:G.992.1
590:G.991.2
585:G.991.1
525:G.723.1
515:G.729.1
510:G.722.2
505:G.722.1
267:Minitel
254:in the
83:scholar
972:Modems
684:G.9972
679:G.9970
674:G.9960
664:G.8262
659:G.7043
654:G.7042
649:G.7041
411:Lists:
230:) for
218:) for
199:) for
187:) for
168:) for
156:) for
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921:is a
833:ITU-R
785:H.450
780:H.324
770:H.323
765:H.320
745:H.263
735:H.261
730:H.248
725:H.245
720:H.241
715:H.239
710:H.235
580:G.988
575:G.987
570:G.984
565:G.983
560:G.811
555:G.806
550:G.798
545:G.783
540:G.729
535:G.728
530:G.726
520:G.723
500:G.722
495:G.719
490:G.718
485:G.711
480:G.709
475:G.707
470:G.706
465:G.704
460:G.703
455:G.165
450:G.114
232:space
201:space
170:space
131:ITU-T
127:modem
90:JSTOR
76:books
923:stub
824:V.92
819:V.24
814:V.23
809:V.11
804:V.10
277:The
220:mark
189:mark
158:mark
123:V.23
121:The
62:news
398:ITU
45:by
968::
313:,
269:.
258:.
238:).
211:).
180:).
144:,
954:e
947:t
940:v
929:.
390:e
383:t
376:v
347:.
236:0
228:A
224:1
216:Z
209:0
205:0
197:A
193:1
185:Z
178:0
174:0
166:A
162:1
154:Z
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
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