Abstract: Telecommunications method, and system suitable therefor, for establishing a connection with a mobile device, for example a GSM mobile radio telephone, of a participant, who is located in a VPLMN, the calling mobile participant in the VPLMN preparing and sending a short message, for example a USSD message, with the desired destination number, which will be passed on to a callback computer, which establishes a connection between the calling mobile participant and the desired destination number, and a connection being established with a called mobile participant in a VPLMN by a callback computer, whose number is assigned to this called mobile participant in the home location register.