This GSM Technical Specification (GTS) specifies the stage 1 description of the enhanced Multi-Level Precedence and Pre-emption Service (eMLPP). This service has two parts - precedence and pre emption. Precedence involves assigning a priority level to a call in combination with fast call set-up. Pre-emption involves the seizing of resources, which are in use by a call of a lower precedence, by a higher level precedence call in the absence of idle resources. Pre-emption can also involve the disconnection of an on-going call of lower precedence to accept an incoming call of higher precedence. The eMLPP service is provided as a network operator s option to a domain of a network. The domain can be the whole network or a subset of the network. The eMLPP service applies to all network resources in the domain that is in common use. The eMLPP service is applicable to all mobile stations in the domain with all or some mobile stations having a respective subscription assigning precedence according to the eMLPP service. eMLPP is a supplementary service and shall be provided to a subscriber for all basic services subscribed to and for which eMLPP applies. NOTE: It is under study whether normal GSM phase 2 mobile stations will be able to be used for this service. The service is described from the service subscriber s and user s point of view, in particular: - the procedure for normal operation with successful outcome; - the action to be taken in exceptional circumstances; - the interaction with other GSM services and features. This specification does not deal with the Man-Machine Interface (MMI) requirements, but makes reference to the appropriate Global System for Mobile communications (GSM) specifications. This specification is applicable to teleseruices 1x and 6x and to all bearer services used in a mobile network according to the digital cellular telecommunications system GSM if eMLPP is provided. Any interaction with other services and/or networks not dealt with in clauses 8 or 9 are outside the scope of this specification.