from 2"d mobile systems fike GSM towards third generation mobile networks is focusing more and more on the provisioning of both classic voice-based services and an easy access to the rapidly spreading world of Internet app~cations.Mong this evolution path, it is mandatory to keep in mind that any new system architecture must be future-proof, i.e. looking forward towards the fu~integration of telephony, multimedia and IT-based services in general.From this point of, new technologies such as the GSM/GPRS standards don't fi~l completely this integration requirement, as they keep voice and data services separate.The ATM, due to its maturity, is sti~the candidate technology for this goal, being able to provide a transport platform for circuit switched services that could easily evolve towards future users needs. In this paper we propose and vafidate an integrated solution using a common transportPemlission to make di~tal or hard copies of all or part of this \vork for personal or classroom use is granted tithout fee provided that copies are not made or distributed for protit or commercial advantage and that copies bear this notice and the full citation on the first page.To copy othenvise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and~ora fee.