Recommendation B.31)
                                USE OF THE INTERNATIONAL SYSTEM OF UNITS (SI)
               The CCITT,
         recommends
               that the various ITU organs, as  well  as  Administrations  and  recognized
         private operating agencies should use in their mutual relations:
               -   the units of the international system of units  (SI)  adopted  by  the
                  General Conference of Weights and Measures (CGPM) and supported by  the
                  International Organization for Standardization (ISO);  this  system  is
                  based on the rationalized form of electromagnetic and  electrotechnical
                  relations;
               -   the letter symbols adopted in the SI system;
               -   rules similar to those of the SI system when it is necessary  to  form
                  names  of  other  units   and   their   symbols   in   the   field   of
                  telecommunications.
               Note - References of relevant publications (updated in 1988).
               BIPM publications: "BIPM Publication: Le  systŠme  international  d'unit‚s"
         (SI).2)
               International Standard ISO 31: "General principles  concerning  quantities,
         units and symbols"
               Parts of International  Standard  ISO  31  of  greatest  interest  for  the
         telecommunications:
               0       (General principles)
               I       (Quantities and units of space and time)
               II      (Quantities and units of periodic and related phenomena)
               V       (Quantities and units of electricity and magnetism)
               VI       (Quantities  and  units  of  light  and  related   electromagnetic
         radiations)
               VII     (Quantities and units acoustics)
               XI      (Mathematical signs and symbols)
               International Standard ISO 1000: "SI units and recommendations for the  use
               of their multiples and of certain other units"
               IEC Publication 27: see Recommendation B.1
               See also ISO Standards Handbook 2 (1982) "Units of measurement".

























         1)      The text of this Recommendation is analogous to that of  Recommendation  430-2  of
         the CCIR.
         2)      The English translation of this publication is published  under  the  title:  "The
           International System of Units", Her Majesty's Stationery Office, London, 1970, and "The
           International System of Units", U.S. National Bureau of Standards, Special  Publication
           330, U.S. Government Printing Office, Washington, DC, 1970.




         Fascicle I.3 - Rec. B.3                   PAGE1