The suggested technical specifications in this document apply to apparatus used by clipicians for the diagnosis of common respiratory diseases and are to be considered as the minimum acceptable standards. Specifications, features and practices which are desirable, but not obligatory, are also presented. It is accepted that a need exists for more sophisticated apparatus for specialised indications (e.g. for use in an academic institution for training or research, or for standardisation of other respiratory equipment). For sophisticated apparatus more stringent specifications apply, some of which can be found in the original documents.