Vodafone demonstrated a service at the Cebit trade show, held in Germany last week, that allows mobile phone customers to call and exchange presence information with users of internet phone services such as Skype.
The prototype application, called Starfish, makes use of two switching systems: the circuit-switched technology used in GSM (Global System for Mobile Communications) networks and the packet-switched VoIP technology, according to Jochen Hertle, director of new business development at Vodafone.
Calls initiated on mobile phones are transmitted over the airwaves via traditional circuit-switching technology. A gateway at the mobile switching station converts the call into IP and forwards the packets to the PC user via their VoIP service.
Vice versa, PC users can initiate a VoIP call, which is converted to circuit-switched signal at the media gateway and transmitted over the airwaves to mobile phone customers.