Article 39 2.

Member States shall encourage the use of the standards or specifications referred to in paragraph 1 for the provision of services, technical interfaces or network functions, to the extent strictly necessary to ensure interoperability of services, end-to-end connectivity, facilitation of provider switching and portability of numbers and identifiers, and to improve freedom of choice for users.

In the absence of publication of standards or specifications in accordance with paragraph 1, Member States shall encourage the implementation of standards or specifications adopted by the European standardisation organisations.

In the absence of such standards or specifications, Member States shall encourage the implementation of international standards or recommendations adopted by the International Telecommunication Union (ITU), the European Conference of Postal and Telecommunications Administrations (CEPT), the International Organisation for Standardisation (ISO) and the International Electrotechnical Commission (IEC).

Where international standards exist, Member States shall encourage the European standardisation organisations to use them, or the relevant parts of them, as a basis for the standards they develop, except where such international standards or relevant parts would be ineffective.

Any standards or specifications referred to in paragraph 1 or in this paragraph shall not prevent access as may be required under this Directive, where feasible.