maintain and control calls or sessions for communications involving user terminals 102 a home subscriber system 118 is coupled to call session control function 114 via a data link 120 home subscriber system 118 includes subscriber profile information including information traditionally associated with a home location register for a mobile subscriber to facilitate ancillary and support functions within multimedia communications system 100 a charging gateway function cgf 122 and a media resource function 124 are provided charging gateway function 122 is coupled to sgsn 106 and ggsn 110 to account for packets passing through these elements for accounting billing and other purposes media resource function 124 is coupled to call session control function 114 and to ggsn 110 media resource function 124 provides resources for conference bridging tones announcements text to speech conversion automatic speech recognition and other service functions for communications through ggsn 110 ggsn 110 couples user terminal 102 to other networks in particular ggsn 110 is coupled to an internet protocol ip network 146 via a data link 148 data link 148 preferably implements a packet based protocol for transfers to a data network data link 148 and ip network 146 provide access to any elements connected to ip network 146 such as for example a computer 154 ggsn 110 is also coupled to a media gateway 130 via a data link 150 media gateway 130 is in turn coupled to a public switched telephone network 142 via a communications link 152 media gateway 130 converts packetized voice received from ggsn 110 to a circuit switched protocol acceptable to the public switched telephone network 142 conversely media gateway 130 converts.