The ITU Radiocommunication Assembly,
considering
a) that there is a need for a common method or procedure for the unambiguous specification and description of the behaviour of telecommunication systems;
b) that a specification of a system is the description of its required behaviour;
c) that a description of a system is the description of its actual behaviour;
d) that a universal method for specification and description should bring economic benefits;
e) that the ITU-T has adopted such a method called the Specification and Description Language (SDL) as described in ITU-T Recommendation Z.100
