Data transmission between first mobile services switching center of first mobile radio system and second mobile services switching center of second mobile radio system

On the basis of the existing mobile radio systems of the so-called second generation, such as the GSM, new mobile radio systems are being developed for the so-called third generation, such as the UMTS, which should be characterized by a higher and flexible transmission rate and should include a package-oriented exchange technology, particularly ATM. In order to create a connection between the different mobile radio systems, a transmission of data between a first mobile services switching center (2GMSC) of a first mobile radio system (2G) and a second mobile services switching center (3GMSC) of a second mobile radio system (3G) is proposed, whereby the mobile services switching centers are connected through an interface (A*), via which useful data is transmitted at a variable useful data transmission rate, in which the useful data is transmitted within data frameworks including a definite pre-determined number of data fields, whereby, depending on the amount of useful data to be transmitted, at least one part of the data fields is first specified with the useful data and then the remaining part of the data fields is specified with dummy bits. In this way, a transmission channel which uses a fixed gross transmission rate (e.g., 64kbit/s), but a variable useful data transmission rate (0-57.6kbit/sec) is created.