Providers of number-based interpersonal communications services shall deploy state of the art measures to limit the reception of unwanted, malicious or nuisance calls by end-users.
1a. Member States shall establish more specific provisions with regard to the establishment of transparent procedures and the circumstances where providers of number-based interpersonal communication services shall override, or otherwise address, the elimination of the presentation of the calling line identification on a temporary basis, where end-users request the tracing of unwanted, malicious or nuisance calls.
Providers of number-based interpersonal communications services shall also provide the called end-user with the following possibilities, free of charge:
(a) to block, where technically feasible, incoming calls from specific numbers or from anonymous sources or from numbers using a specific code or prefix referred to in Article 16(3a); and
(b) to stop automatic call forwarding by a third party to the end-user’s terminal equipment