"This Technical Specification provides the stage 1 description for a lawful interception function to be implemented in a given GSM PLMN in order for a network operator to be able to fulfil national lawful requirements. It shall be noted that national variation may exist but it is not the intention for this specification to encompass all of them. The purpose of this specification is to cover the options which may be selectable according to national regulations or as required by the GSM PLMN operator in co-operation with their suppliers. In the preparation of this specification general reference was made to the European Union Council Resolution@ January 1995: ""International Requirements for the Lawful Interception of Telecommunications""."