1、ITU-T RECMN*T-32 AMD*3 96 4862593 Ob38355 323 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 TERMINALS FOR TELEMATIC SERVICES T.32 (07/96) ASYNCHRONOUS FACSIMILE DCE CONTROL - SERVICE CLASS 2 Amendment 1 to ITU-T Recommendation T.32 (Previousl
2、y “CCITT Recommendations“) ITU-T RECMN*T.32 AMD*3 96 48b257L 0638356 26T FOREWORD The -T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (IT). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Reco
3、mmen- dations on them with a 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 t
4、opics. The approval of Recommendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12.1993). Amendment 1 to IT-T Recommendation T.32, was prepared by IT-T Study Group 8 (1993-1996) and was approved under the WTSC Resolution No. 1 proce
5、dure on the 3rd of July 1996. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1996 All rights reserved. No part of this publication may be reproduced or utilized in any f
6、orm or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*T.32 AMD*I 96 YB62571 0638357 LTb CONTENTS 1 Additions to Table 21 . 2 Add the following new Annex C to Recommendation T.32 Annex C -Procedure for service clas
7、s 2 support of V.34 modems C.l Introduction C.2 References . C.3 Functions C.4 Definitions and conventions . C.5 Initial V.34 rate controls and indications C.6 V.8 negotiation with DTE control C.7 Sample sessions Page 1 1 1 1 2 2 2 2 4 5 i Recommendation T.32 I Amd.1 (07/96) ITU-T RECMNMT-32 AND* V.
8、34 modems (new Annex UT.32). ii Recommendation T.32 / Amd.1 (07/96) ITU-T RECIINUT-32 AMD*l 96 4862593 Ob38359 T79 W Value O *I *2 *3 *4 5-7 *8 *9-F Amendment 1 to Recommendation T.32 Description l-D Modified Huffman (Rec. T.4) 2-D Modified read (Rec. T.4) 2-D Uncompressed mode (Rec. T.4) 2-D Modifi
9、ed read (Rec. T.6) Single-progression sequential coding (Rec. T.85) for capabilities, combinations of Recs. T.85, T.6 and T.4 Single-progression sequential coding (Rec. T.85) optional u) for capabilities, combinations of Recs. T.85, T.6 and T.4 ASYNCHRONOUS FACSIMILE DCE CONTROL - SERVICE CLASS 2 (G
10、eneva, 1996) 1 Additions to Table 21 TABLE 21R.32 T30 session subparameter codes Function Data Compression Format 2 Add the following new Annex C to Recommendation T.32 Annex C Procedure for service class 2 support of V.34 modems (This annex forms an integrai part of the Recommendation) C.l Introduc
11、tion C.l.l V.34 modems References in this annex to user data rates greater than 28 o00 bitsls are in anticipation of an amended version of Recommendation V.34 expected in 1996. Recommendation V.34 is standardized for use on the GSTN at rates up to 33 600 bids. Recommendation V.34 defines two modes o
12、f operation: 0 0 Duplex (clauses 5,7,8,9, 10.1 and 11). Haif-duplex (clauses 5,7,8,9, 10.2 and 12). Half-duplex mode supports two channels: Half-duplex high-speed primary channel. Duplex low-speed control channel. Recommendation T.32 I Amd.1 (07/96) 1 ITU-T RECMNxT-32 AflD+L 96 4862.591 ObLB3b0 790
13、C.1.2 T.30 procedures for use with V.34 modems Procedures for V.34 facsimile are defined for both V.34 modes: 0 Annex W.30, with revisions, defines Group 3 facsimile for duplex V.34. 0 Annex FT.30, defines Group 3 facsimile procedures for haifduplex V.34. This annex defines procedures for a service
14、class 2 facsimile DCE to implement Annex Cl.30 or Annex FT.30 with V.34 modems. C.1.3 V.8 call negotiation For all uses of Recommendation V.34, procedures defined in Recommendation V.8 are required for negotiating the cai1 type. For T.30 operation, this includes determination of the V.34 mode (duple
15、x or haifduplex) and the direction of the message (send or receive) if haif-duplex is used. This annex defines simple extensions to Recommendation T.32 to support V.8 negotiation implemented by the DCE but hidden from the DTE. Annex AN.25 ter defines optional procedures for a service class 2 facsimi
16、le DCE to implement V.8 call negotiation driven directly by the DTE. C.2 References - IT-T Recommendation V.34 (1996), A modem operating at data signalling rates of up to 33 600 bits for use on the general switched telephone nenuork and on leased point-to-point 2-wire telephone-type circuits. C.3 Fu
17、nctions A DCE compliant with this annex shall provide the following functions to the DTE: a) procedures to condition V.8 call type negotiation; b) procedures to constrain the primary channel rate; and c) DTE indication of the primary channel rate. C.4 Definitions and conventions The following defini
18、tions apply, in addition to those defined in Recommendations T.30, T.31 or V.34: C.4.1 sending DCE: The DCE which transmits primary channel data in haif-duplex mode, C.4.2 recipient DCE: The DCE which receives primary channel data in half-duplex mode. C.5 Initial V.34 rate controls and indications C
19、.5.1 Additional BR subparameter codes for V.34 rate controls Table 21 defines the BR subparameter, for use in setting and indicating the message (Phase C) bit rate. For use with V.34 facsimile Annex Cf.30 or Annex F/T.30), the following new codes are defined, in addition to values 0-5 defined in Tab
20、le 2 1. See Table C. 1. 2 Recommendation T.32 / Amd.1 (07/96) TABLE C.lm.32 BR value O - 5 6 7 8 9 A B C D E Rate in +FCU+FiS description +FCS description bis 2400 2400 bitis preferred 2400 bitls selected _. - - 14 400 14400 bis selected 16800 16 800 bis preferred 16 800 bitis selected 19 200 19 200
21、 bitls preferred 19 200 bitis selected 21 600 21 600 bids preferred 21 600 bis selected 24 O00 24 o00 bitls preferred 24 O00 bitis selected 26 400 26 400 bis preferred 26 400 bitis selected 28 800 28 800 bis preferred 28 800 bitis selected 31 200 3 1 200 bis selected 33 600 33 600 bitls selected Res
22、erved for future modulations 14400 bitis preferred all with V.8 optional 3 1 200 bitls preferred 33 600 bitis preferred all with implied Rec. V.8 Reserved for future modulations To indicate capability to support Recommendation V.34, the DCE shall include any supported BR values (e.g. 6-D) in respons
23、e to +FCC=?, +FIS=? and +FCS=? commands. EC value To indicate preference for V.34 operation, the DTE may set (or accept a default setting of) the BR subparameter to values 6 or above. Description 1 To indicate connection with V.34 procedures, the DCE shall indicate the appropriate value in the +FCS:
24、,BR subparameter. If the rate is 14 400 bids or below, there is no indication of modulation type. O 1 C.5.2 Selection and indication of V.34 mode - Rec. T.30, without ECM Annex A.30 or Annex Ff.30 with V.34 HD The EC subparameter defined in Table 21 defines codes for Recommendations T.30, T.30 with
25、ECM and Annex CR.30. The descriptions of these subparameters are amended as follows (see Table C.2): 2 3 TABLE C.uT.32 Annex m.30 , half-duplex Annex Cef.30, including V.34 FD To indicate support for half-duplex V.34, the DCE shall include the EC value 1 in response to +FCC=?, +FIS=? and +FCS=? comm
26、ands. Recommendation T.32 / Amd.1 (07/96) 3 _ ITU-T RECMN*T*32 AMD*L 7b U 48b2571 Ob183b2 5b3 To indicate support for duplex V.34, the DCE shall include the EC value 3 in response to +FCC=?, +FIS=? and +FCS=? commands. To indicate preference for V.34 operation, the DTE may set (or accept a default s
27、etting of) the EC subparameter to values of 1 or 3. A DCE that implements Annex CR.30 for duplex V.34 may also support Annex Fm.30 for half-duplex V.34; if so, the default +FCC EC subparameter shall be 3. To indicate connection with V.34 procedures, the DCE shall indicate the appropriate value in th
28、e +FCS: EC subparameter. C.5.3 y.8 message direction setup For use with V.8 call type negotiation, the direction of the first message must be determined before the call is placed and answered. Therefore, the DTE shall preconfigure the DCE. For the calling DCE, the T.32 DCE default value for message
29、direction is to send a facsimile, unless +FSP=l and +FCR=l. To configure for polling, the DTE shall ensure that +FSP and +FCR are set. For the answering DCE, the T.32 default value for message direction is to receive a facsimile, unless +FLP=l andor +FCR=. To configure for being polled, the DTE shal
30、l set +FLP=l. For V.34 operation, direction indication is identical to that defined in Tables 11 and 12. If the first message is to send a facsimile, the callinghending DCE will not indicate +WO as part of the D command response, and the answeringlreceiving DCE will indicate +FCS as part of the A co
31、mmand response. If the first message is for polling, the callin-gheceiving DCE will indicate +FPO as part of the D command response, and the answeringlsending DCE will indicate +FTC as part of the A command response. C.6 V.8 negotiation with DTE control The DCE may support procedures to allow a DTE
32、to conduct the V.8 negotiation. The procedures defined in Annex AN.25 fer may be used. C.6.1 Preconfiguration of initiai V.34 rate(s) Preconfiguration of V.34 rates shall be supported using the same BR subparameter, as defined in C.5 above, If the DCE supports the +F34 parameter (B.6.1ir.31), it may
33、 be used instead, which also allows the control carrier to be controlled by the DTE. If +F34 is used, then the DCE shall ignore +FIS BR subparameter for that call setup. C.6.2 Transition from V.8 negotiation After V.8 negotiation is complete, the Annex Cir.30 or Annex Fir.30 procedures must commence
34、. These begin with V.34 carrier training, as preconfigured by the V.8 negotiation (direction, half- or duplex mode and rates). The DCE shall decode V.8 negotiation to detect these selections, and conduct V.34 carrier training, and then commence T.30 Phase B operation. The DCE responses are described
35、 above. The DTE shall respond with any additional configuration commands, and the appropriate +FDT or +FDR commands, and proceed as defined in 8.3.3 or 8.3.4. 4 Recommendation T.32 / Amd.1 (07/96) ITU-T RECMN*T*32 AVD*3 96 = 4862593 0638363 4TT C.7 Sample sessions In these examples, actions between
36、the DTE and DCE on both the originating and answering side are illustrated. These are simple send and receive examples, derived from Tables II. 1 and II.2. C.7.l Optional T.30 frames are omitted. +FNR=l,l, +FIS and +FCS subparameters other than BR and EC are not shown. Originate and send a two page
37、facsimile with V.34 half-duplex I commands DTE 1 AT+FCLASS=2.1 ATDcdid string AT+FDT c1 st.page dato cmps AT+FDT c2nd page data DCE responses OK OK +FCS:9,1, CONNECT OK CONNECT +FHS:OO OK Local DCE action Set class 2 Set for Rec. V.34, Annex M.30, Annex Cf.30 or Annex Fir.30 Off-hook, did, send CNG
38、detect ANSam send CM get JM send U negotiate Rec. V.34 begin control channel get DIS send DCS get CFR switch to primary channel send page FCD switch to control channel send MPS get MCF switch to primary channel send page 2 FCD switch to control channel send EOP get MCF send DCN hangup Remote station
39、 action detect ringing answer detect CNG send ANSam get CM send JM get CJ negotiate Rec. V.34 begin control channel send DIS get DCS send CFR switch to primary channel get page data switch to control channel get MPS send MCF switch to primary channel get page 2 FCD switch to control channel get EOP
40、send MCF get DCN hWPP Notes Rec. T.30 selected with JM signal from remote terminal the remote indicated 28 800 bih ability in this example, 24400 bi/s is selected Recommendation T.32 / Amd.1 (07/96) 5 ITU-T RECMNMT.32 AMD*3 96 4862593 ObL8364 336 = AT+FIS=,D , 3 , ATA C.7.2 Answer and receive a two-
41、page facsimile with V.34 haif-duplex OK RING +FCO OK AT+FCLASS=2.1 AT+FDT AT+FDR AT+DR +FCS:,B,.,J, CONNECT +FPs: 1 ,O,O,O +FET:O OK CONNECT 2nd page dato +FPs:l,lo,o,o,o +ET2 +FHS:OO OK Local DCE action Set class 2 Set for Rec. V.34, Annex m.30, Annex m.30 or Annex Ff.30 detect ringing answer detec
42、t CNG send ANSam get CM send JM get CJ negotiate Rec. V.34 begin control channel send DIS get DCS send CFR switch to primary channel get page 1 FCD switch to control channel get MPS send MCF switch to primary channel get page 2 FCD switch to control channel get EOP send MCF get DCN hangup Remote sta
43、tion action off-hook. dial send CNG detect ANSam send CM get JM send CJ negotiate Rec. V.34 begin control channel get DIS send DCS get CFR switch to primary channel send page 1 FCD switch to control channel send MPS get MCF switch to primary channel send page 2 FCD switch to control channel send EOP
44、 get MCF send DCN hangup Notes select max rate of 33 600 bitls Rec. T.30 selected with JM signal from remote terminai the remote indicated 28 800 bitls ability in this example, 28 800 bitls is selected 6 Recommendation T.32 / Amd.1 (07/96) ITU-T RECMN*T*32 AflD*1 96 48b259L 0638365 272 9 Printed in Switzerland Geneva, 1996
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