04.013GPPMobile Station - Base Station System (MS - BSS) Interface General Aspects and PrinciplesTS
MS-BSS interface Technical Specifications should allow:
i) different types of mobile stations and terminal equipment to use the same standard interface;
ii) portability of MSs within the system area of the GSM system;
iii) separate evolution of both mobile stations and network equipment technologies and configurations;
iv) calls to a terminal using the same code (call number) no matter in what country it is actually located;
v) connections of an MS to the ISDN network so that only the radio channel capacity and the ISDN protocol are limiting factors.