Article 18 Paragraph (1) Recording the use of telecommunications services shall be the obligation of the operator, the implementation of which shall be carried out in stages and shall only be applicable for long distance direct dialing service (SLJJ) and international direct dialing (SLI), to the extent requested by the telecommunications service user. Recording the use of telecommunications services is the detailed invoice data record (billing) which is used to evidence the use of telecommunications services. Paragraph (2) Self-explanatory. Paragraph (3) Self-explanatory. Article 19 When a telecommunications network is connected with a number of other networks operating the same services, the user of the said network must be guaranteed the freedom to choose one of the connected networks through a stipulated numbering system. In principle, the user is entitled to choose a network operator and/or telecommunications service to channel his telecommunications connection. In implementing this connection, network operator and/or telecommunications services operator may change the route of the user’s connection to other network operators without the knowledge of the user. If this occurs, this situation is contrary to the principle of fair competition, which may harm both the operator as well as the user.