1、STD-ITU-T RECMN R-22-ENGL L9b W 48b2591 ObZL1135 TU2 m INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES R: TELEGRAPH TRANSMISSION Vo ice-f req uen cy tel eg ra ph y R.22 (08/96) Data over voice I9 200 bits modem standarized for use on telephone netwo
2、rk subscriber lines ITU-T Recommendation R.22 (Previously CCITT Recommendation) ITU-T R-SERIES RECOMMENDATIONS TELEGRAPH TRANSMISSION Telegraph distortion R. 1 -R. 19 - ,i . Special cases of alternating current telegraphy Transmission quality Correction of signais Telegraph maintenance Time-division
3、 multiplexing Transmission quality above 50 bauds Definitions Availability and reliability of international telegraph circuits R.40-R.49 R.50-R.59 R.60-R.69 R.70-R99 R.100-Rl19 R.120-R. 139 R.140-R.149 R. 150-R. 159 For further details, please refer to ITU-T List of Recommendatiom. - - STD-ITU-T REC
4、MN R*ZZ-ENGL 177b W Li8b259L Ob24137 885 FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations on them with a
5、 view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recom
6、mendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12,1993). ITU-T Recommendation R.22 was prepared by ITU-T Study Group 14 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 16th of August 1996. NOTES 1.
7、 telecommunication administration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a 2. follows: The status of annexes and appendices attached to the Series R Recommendations should be interpreted as - an annex to a R
8、ecommendation forms an integral part of the Recommendation. - an appendix to a Recommendation does not form part of the Recommendation and only provides some complementary explanation or information specific to that Recommendation. O ITU 1996 All rights reserved. No part of this publication may be r
9、eproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing fiom the ITU. Recommendation R22 (08196) 1 1 2 3 4 5 6 7 8 11 . . STD-ITU-T RECMN R-22-ENGL 199b E Vb2591 b24138 711 m CONTENTS Scope Normative references
10、. Line signals Transmission level Data signalling and modulation rate . Interchange circuits 6.1 List of interchange circuits . 6.2 Circuit 109 threshold 6.3 Timing arrangements Scrambler/descrambler . Test loop arrangement Recommendation R.22 (08196) Page 1 1 1 2 2 Recommendation R.22 DATA OVER VOI
11、CE 19200 bit/s MODEM STANDARIZED FOR USE ON TELEPHONE NETWORK SUBSCRIBER LINES (Geneva, 1996) 1 Scope This Recommendation defnes a modem for use on telephone network subscriber lines which can also be used on leased lines. On Subscriber lines, taking into consideration that there exist and will come
12、 into being other modems designed to meet the requirements of Administrations and users, this Recommendation in no way res-icts the use of any other modems. The principal characteristics of the standardized modem are as follows: a) b) digital data transmission on the telephone network subscriber lin
13、e, ensuring the possibility of telephone communication over the same subscriber line; duplex mode of operation, with separation of the receiving and transmitting directions by fkequency division; asynchronous mode of operation at up to 19 200 bids and synchronous at 1200, 2400, 4800, 9600 and 19 200
14、 bids; c) d) use of frequency modulation; e) NOTE - Only one mode of operation can be provided in the modem (either asynchronous or synchronous), by decision of remote control of the establishment of loop 2 as defined in Recommendation V.54. the Administration concerned. 2 Normative references The f
15、ollowing Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision: all users of this Rec
16、ommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. IS0 21 10:1989, Information technology - Data communication -
17、25-pole DTE/DCE interface connector and contact number assignments. ITU-T Recommendation V.24 (1993), List of definitions for interchange circuits between Data Terminal Equipment (DTE) and Data Circuit-terminating equipment (DCE). - ITU-T Recommendation V.28 (1 993), Electrical characteristics for u
18、nbalanced double-current interchange circuits. - - 3 Line signals 3.1 Characteristic fiequencies for the route ffom exchange to subscriber are as follows: - - Characteristic frequencies for the route from subscriber to exchange are as follows: - - F(A) (symbol 1, mark): 50 h 0.1 kHz; F(Z) (symbol O,
19、 space): 60 * 0.1 kHz. 3.2 F(A) (symbol 1, mark): 95 h 0.2 kHz; F(Z) (symbol O, space): 105 f 0.2 kHz. Recommendation 2.22 (08196) 1 STDnITU-T RECMN R-22-ENGL L77b qb257L Ob24LLiO 37T m No. 4 Transmission level The transmission level for both channels shall be -3 f 1 during this period the received
20、data line signal is to be transmitted over circuit 104. For a received line signal less than -48 dBm, circuit 109 will be maintained in the OFF condition and the binary 1 signal is to be transmitted over circuit 104. The condition of circuit 109 for levels between -43 dBm and -48 dBm is not specifie
21、d, except that the signal detector shall exhibit a hysteresis action such that the level at which the OFF to ON transition occurs is at least 2 dB greater than that for the ON to OFF transition. 2 Recommendation R.22 (08196) STD-ITU-T RECMN R-22-ENGL L79b 48b259L Ob2iLiL 20b When line attenuation is
22、 known, Administrations should be perniitted at the time of modem installation to change the above levels of the received line signal detectors to less sensitive values (e.g. -33 dBm and -38 dBm, respectively). The time of OFF to ON transition and vice versa is 10 f 5 ms. 6.3 Timing arrangements The
23、 modem should provide the data terminal equipment with transmitter signal element timing, circuit 114, and receiver signal element timing, circuit 115, at any data signalling rate used in the modem. The transmitter signal element timing may be originated in the data terminal equipment and be transmi
24、tted to the modem via circuit 113. 7 Scrambler/descrambler 7.1 in the modem to provide the synchronous mode of operation. A self-synchronizing scrambler/descrambler having the generating polynomial 1 + x4 + r7 shall be included 8 Test loop arrangement 8.1 The modem shall be conditioned to test the d
25、igital line between the telephone station and the subscriber by establishing loop 2, when the binary signal from the receiving side output of the modem is applied to the input of its transmitting side, and circuit 104 to the DTE is maintained in the binary 1 condition. 8.2 Loop 2 may be established
26、manually or automatically. 8.3 Automatic control of the loop test procedure may be as follows: a) the carrier towards the subscriber modem will be removed from the line (e.g. circuit 140 goes ON) for more than 20 ms, after which the subscriber modem recovers the carrier; b) in response to the short
27、removal and subsequent reappearance of the carrier in the subscriber modem, loop 2 shall be established for a period of 30 s; the subscriber modem, when the loop2 condition is terminated (30 s), will be returned to normal operation. c) Recommendation R.22 (08/96) 3 ITU-T RECOMMENDATIONS SERIES hies
28、A ieries B ieries C ;,ries D Series E Series F Series G Series H Series I Series J Series K Series L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V Series X Series Z Organization of the work of the ITU-T Means of expression General telecommunication statist
29、ics General tariff principles Telephone network and ISDN Non-telephone telecommunication services Transmission systems and media Transmission of non-telephone signals Integrated services digital network Transmission of sound-programme and television signals Protection against interference Constructi
30、on, installation and protection of cables and other elements of outside plant Maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Maintenance: international sound-programme and television transmission circuits Specifications of measuring equ
31、ipment Telephone transmission quality Switching and signalling Telegraph transmission Telegraph services terminal equipment Terminal equipments and protocols for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communication Programming languages Printed in Switzerland Geneva, 1996
