FIELD: system and device for control of signalling between party of mobile station and external service center, for example, message transmission center. SUBSTANCE: signalling control is accomplished with making use of non-structurized data of additional service that are analyzed by the processing unit of non- structurized data of additional service of the registration point register, as a result of which the applied program of clear transfer to external centers gets activated if the non-structurized data of additional service do not conform to the service determined in the registration point register. The applied program of clear transfer to external centers establishes dialogue between the party of the mobile station and the desired external service center with making use of non-structurized data of additional service. This allows the party of the mobile station to get access to the message transmission services by transfer of one service code. Besides, the operator is not occupied at getting access to service and may reply to any incoming calls at a simultaneous access to service. EFFECT: conversation may be held at simultaneous getting of access to information service. 40 cl, 6 dwg
