The hydraulic test equipment used for generating vibration has a wide range of characteristics which can be evaluated in many different ways. In order to enable the possibilities afforded by test equipment from different sources to be compared, this International Standard establishes a) a list of the characteristics; b) the standard method of obtaining certain of these characteristics. This International Standard provides two levels of description to be used in describing the test equipment, as follows: a) level 1 description; b) level 2 description. It gives, for each level of description, chosen by agreement between the user and the manufacturer, a list of the characteristics to be described by the manufacturer in his tender as well as a list of technical documents to be supplied with the equipment. Furthermore, the manufacturer's literature shall contain at least the characteristics corresponding to a level 1 description. This International Standard applies to the following equipment : — hydraulic vibration generators [actuators, servovalves, all or part of the position control device and, if fitted, the static force compensating device (see clauses 5, 6 and 7)); — the servovalve control devices (see clauses 5, 6, and 8); — the hydraulic power systems (see clauses 5, 6 and 9); — the complete hydraulic vibration generator systems (see clauses 5, 6 and 10).