VOICE MESSAGE CONNECTION CONTROL FOR PSTN AND N-ISDN SUBSCRIBERS IN ATM SWITCHING-SYSTEM

The ATM switching system accommodating the public switched telephone n etwork (PSTN) and narrowband ISDN (N-ISDN) subscribers should ensure t he continued support of existing services and applications and guarant ee the same quality of voice services for the telephone users [1]. The voice message connection control discussed in this paper is one of th e various technical issues for voice services in the interworking func tion unit, IWF between asynchronous transfer mode (ATM) node and exist ing synchronous transfer mode (STM) node [2]. We describe the technica l points for the implementation of the voice message connection contro l with the consideration of the development time and cost. And then we discuss several technical problems such as mapping pulse code modulat ion PCM coded voice data into an ATM cell, different switching operati on, keeping performance of the ATM-PSTN interworking system and then p resent benefits of the voice message connection control processing fro m the hardware/software point of views.