functional specification
as defined in 87/95/EEC: Council Decision of 22 December 1986 on standardization in the field…, Article 1, point (10)
the specification which defines, in the field of telecommunications, the application of one or more open system interconnection standards in support of a specific requirement for communication between information technology systems (standards recommended by such organizations as the 'Comité international télégraphique et téléphonique' (CCITT) or the CEPT);