This basic Recommendation describes resistibility tests for all telecommunication equipment against overvoltages and overcurrents for use by network operators and manufacturers. This Recommendation applies to all telecommunication equipment connected to external or intra-building metallic conductors. It should be read in conjunction with [ITU-T K.11] and [ITU-T K.39] which deal with the general economic and technical aspects of protection. This Recommendation does not specify either test levels or particular acceptance criteria for specific equipment. The appropriate test levels and test points are contained in the specific product family or product Recommendation. Therefore@ this Recommendation has to be used together with the product family or product Recommendation dealing with the resistibility requirements relevant to the equipment to be tested. If a product family or product Recommendation or clause of it differs from this basic Recommendation@ the product family or product Recommendation applies. As product Recommendations are updated@ they should be coordinated with and refer to this Recommendation. This Recommendation assumes that the earthing and bonding configurations comply with the appropriate Recommendation related to the type of installation. The tests are type tests and@ although they are applicable to a complete system@ it is recognized that they may be applied to individual items of equipment during development and design work. In performing the tests@ it is necessary to take into account any conditions@ either in the unit under test or elsewhere@ which may affect the results. Electrostatic discharge (ESD) testing is not covered by this Recommendation and [IEC 61000-4-2] should be followed.