Recommendation B.191) 
                            ABBREVIATIONS AND INITIALS USED IN TELECOMMUNICATIONS
               The CCITT,
         considering
               (a) the rapid increase in the number of abbreviations and initials used  in
         the texts of the CCIs;
               (b) that it is sometimes difficult  to  find  the  precise  meaning  of  an
         abbreviation or acronym appearing in a text of the CCIs,
         recommends
               (1)  that,  with  the  exception  of  abbreviations  frequently   used   in
         telecommunications, abbreviations and acronyms should not be used in the texts of
         the CCIs unless they make the text easier to read, i.e. when an abbreviation  may
         be used several times in the same text;
               (2)  that,  with  the  exception  of  abbreviations  frequently   used   in
         telecommunications the first time an abbreviation is used in  a  particular  text
         its full meaning should be given, either  in  the  body  of  the  text  or  in  a
         footnote;
               (3) that at alphabetical list of the abbreviations used in the CCI  volumes
         should be published either at the end of each volume or in a separate                                                       fascicle2),
         3) 
               (4) that for abbreviations specific to certain fields, the Administrations,
         CCI Secretariats and other participants in the work of the CCIs  should  use  the
         abbreviations which appear in the publications listed in Appendix I.
                                                 APPENDIX I
                                      (to Recommendation B.19)
                           References to lists of specific abbreviations
         I.1    Frequency and wavelength bands
               See Recommendation B.15.
         I.2    Alphabets, codes, routing codes and identities
               See the relevant CCITT Recommendations (Index of the  Blue  Book,  Fascicle
         I.4).
         I.3    Codes contained in the Radio Regulations
         I.3.1  Designation of emissions: Article 2.
         I.3.2  Symbols for the various types of antenna: Appendix 2, Section III.
         I.3.3  Q code, general section (QRA to QUZ): Appendix 13, Section I.
         I.3.4  Miscellaneous abbreviations: Appendix 13, Sections I and II.
         I.3.5  SINPO and SINPFEMO codes: Appendix 15.
         I.4    Abbreviations used by the ITU for the names of countries
               See the Preface to the International Frequency List,  Table  I.  (Different
         abbreviations have been approved by ISO.)
         I.5    Acronyms of international organizations involved in telecommunications
               See the ITU "List of Adddresses", S 3.
         I.6    Symbols and names for units
         I.6.1  Recommendation B.3 gives the  sources  to  be  used.  This  Recommendation
         refers to IEC Publication 27 and to ISO International Standards 31 and 1000.
         I.6.2  Recommendation B.14: Terms  and  symbols  for  information  quantities  in
         telecommunications.
         I.6.3  Recommendation B.15: (Note 2) - Frequency unit.
         I.6.4   Recommendation  B.12:   Use   of   the   decibel   and   the   neper   in
         telecommunications.
         I.6.5  Recommendation B.18: Traffic intensity unit.
         I.7    Letter symbols
               Recommendation  B.1:  "Letter  symbols  for  telecommunications"   provides
         guidelines to be followed to simplify  the  reading  of  documents  dealing  with
         telecommunication techniques;  it  refers  to  IEC  Publication  27  and  to  ISO
         International Standard 31 for letter symbols to represent physical quantities and
         mathematical operations.
         I.8    Chemical symbols
               See the table published by the International  Union  of  Pure  and  Applied

         1)      CCIR Recommendation 666 is concerned with the same subject.
         2)      An alphabetical list of the abbreviations used in the CCITT volumes  is  published
         in Part V of this fascicle.
         3)      CCIR Recommendation  666  contains  in  its  Appendix  I,  a  list  of  about  100
           abbreviations, in general use by the CCIR  Study  Groups  and  which  are  arranged  by
           subject together with the corresponding abbreviations in the three working languages.



         Fascicle I.3 - Rec B.19 .           PAGE1

         Chemistry (IUPAC).




































































         PAGE2      Fascicle I.3 - Rec. B.19