7_3_03.txt

传真编程的一些文档

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       Note  - There may also be operating methods which will  allow  mes-
       sages  to  be received by more than one station (multipoint connec-
       tion).
                                                  Table 1/T.30 [T1.30], p.




       1.3         Station identification


            1.3.1 For the purpose of classifying  an  automatic  facsimile
       station  as  a  non-speech  terminal, a tone must be transmitted to
       line. As both  automatic  calling  and  called  facsimile  stations
       transmit tones to line during call


       establishment, a normal telephone user  who  becomes  inadvertently
       connected  to  one will receive tone signals for a period of suffi-
       cient duration to indicate clearly to him that  he  is  incorrectly
       connected.

            1.3.2 Additionally an automatic  verbal  announcement  may  be
       used which can provide station identification.


       1.4         General provisions


            1.4.1 The control signals  specified  in  this  Recommendation
       have  been  chosen  in such a way that the telephone service is not
       affected.


            1.4.2 If any malfunction of the facsimile procedures described
       in this Recommendation is detected, the call should be released.

            1.4.3  Where  the  called  station  has  automatic   facsimile
       apparatus  which  is  not  ready  or  not able to operate, the call
       should not be answered automatically.


            1.4.4 This Recommendation includes  procedures  for  switching
       from facsimile to speech regulations of the Administrations.










       1.5         Optional provisions


            1.5.1 The operator at each station may have the possibility of
       calling  the  other  station at any time during the progress of the
       facsimile procedure (see S 2.2 below).


            1.5.2 The procedures in this Recommendation allow a  facsimile
       station  to  transmit and/or receive several documents successively
       without the aid of an operator.

            1.5.3 This Recommendation includes procedures for  incorporat-
       ing  a unique station identification command if required to prevent
       unauthorized stations from demanding a message.

            If enhanced security is required, this may be provided by  the
       use of the non-standard facilities frame.


       2       Explanation of terms used



       2.1         Facsimile station main functions


            One or more equipments at the end of the line providing  three
       main  functions.


       2.1.1         Call establishment and call release


            The establishment and release of a connection according to the
       normal rules of using the general switched telephone network.


       2.1.2         Procedure


            To  identify,  to  supervise  and  to  control  the  facsimile
       transmission according to a protocol.


       2.1.3         Message transmission


            To transmit and/or receive the facsimile message.


       2.2         Time sequence of a facsimile call  | see Figure 1/T.30)



                                                         FIGURE 1/T.30, p.










       2.3         Description of phases



       2.3.1         Phase A - Call establishment


            Call establishment can be realized manually  and/or  automati-
       cally.



       2.3.2         Phase B - Pre-message procedure


            The pre-message procedure consists of  the  identification  of
       capabilities and the commanding of the chosen conditions as well as
       the confirmation of acceptable conditions.

            When connection is established between apparatus operating  in
       accordance  with  this  Recommendation and apparatus operating in a
       non-CCITT manner,  the  equipments  should  disconnect  before  the
       in-message  procedure unless both equipments include optional, com-
       patible, procedures.


       2.3.2.1         Identification section


               -         group identification,

               -         confirmation for reception,

               -         subscriber identification (option),

               -         non-standard facilities identification (option).


       2.3.2.2         Command section


               -         group command,

               -         phasing / training ,

               -         synchronization,

               -         as well as the following optional commands:

               -         non-standard facilities command,

               -         subscriber identification command,

               -         polling (send) command,

               -         line conditioning ,










               -         echo suppressor disabling


       2.3.3         Phase C1 - In-message procedure


            The in-message procedure takes place at the same time as  mes-
       sage   transmission   and  controls  the  complete  signalling  for
       in-message  procedure,  e.g., in-message   synchronization,   error
       detection and correction and line supervision.


       2.3.4         Phase C2 - Message transmission


            Message transmission procedure is covered by  the  appropriate
       Recommendation for the equipment.


       2.3.5         Phase D - Post-message procedure


            The post-message procedure includes information regarding:

               -         end-of-message signalling,

               -         confirmation signalling,

               -         multipage signalling,

               -         end-of-facsimile procedure signalling.


       2.3.6         Phase E - Call release


            Call release shall be realized manually and/or automatically.


       3       Description of a facsimile call



       3.1         Phase A - Call establishment


            The establishment of a facsimile call may be  realized  either
       manually,  if  an  operator  is in attendance, or automatically. To
       accomplish this, four operating methods have been defined.



       3.1.1         Operating method 1
       _________________________
       See Appendix II for abbreviations  used in this  Recom-
       mendation.










            Manual operation at both the calling and called station.  Fig-
       ure 2/T.30 indicates the operators' actions required to establish a
       call.
                                  H.T. [T2.30]

       _________________________________________________________________________________________________________
                         Call event No.                           Calling station            Called station
       _________________________________________________________________________________________________________
                                1                            {
        Operator hears dial tone and dials desired number
                                }
                                2                           Operator hears ringing tone    {
            Call rings and operator answers the call
                                }
                                3                           Verbal identification         Verbal identification
                                4                            {