A telecommunications system and method is disclosed for providing interoperability between a cellular system's direct access to the Internet and the telephony service provided by the Public Switched Telephone Network (PSTN), in order to allow a mobile subscriber to receive calls from the PSTN while engaged in data communication, for example, over the Internet. When a Mobile Station (MS) has an active connection to a server or router running Internet Protocol, an incoming PSTN call can be forwarded to a voice gateway within the serving Mobile Switching Center/Visitor Location Register (MSC/VLR), which transforms the call to an Internet phone call. During the direct access connection to the Internet, the MS can signal specific information, using, e.g., a prefix, to activate the call forwarding to voice gateway feature.