the disconnection. During the first month following disconnection, however, it must be possible to call the subscriber con-cerned. The subscriber shall also be able to contact the emergency number 112 for an equal length of time. In cases where a subscriber has fraudulently attempted to avoid payment or to transfer responsibility to an unrelated party, an electronic communications undertaking may disconnect the service in question without warning. Article 40 Limits on liability Electronic communications undertakings may, in their terms of service, exempt themselves from liability for any damages resulting from connection failure, disruption of electronic communications or other disturbances which may occur in the operations of the electronic communications network, whether this can be attributed to a breakdown of the line, a failure in the connecting station or other causes. Limits on liability are, however, limited to damages not resulting from major errors on the part of the undertaking's staff. Article 41 Quality of service PTA may issue rules concerning the quality of electronic communications services and presentation of information published to enable users to have access to comprehensive, comparable and easily understandable information. CHAPTER IX Protection of personal data and privacy Article 42 Traffic data Traffic data relating to users processed and stored by electronic communications undertakings must be destroyed or made anonymous once it is no longer needed for the purpose of transmission of a communication. Traffic data necessary for the purposes of subscriber billing and intercon-nection payments may be stored until the end of the period during which the bill may be challenged or until it becomes obsolete. If a subscriber has given his/her consent, an electronic communications undertaking may process the data referred to in the first paragraph, for the purpose of marketing electronic communications or the provision of value-added services to the extent necessary for such services or marketing. This consent may be withdrawn at any time. A service provider must inform the subscriber in advance of the types of traffic data which are processed and of the duration of such processing. Processing of traffic data as provided for in this Article must be restricted to persons acting under the authority of electronic communications undertakings who handle billing or traffic management, customer 20/34