Wireless phone with interface to different networks

A communications system and device in which wireless data devices designed for communications over a packet switching network such as the Internet, and wireless telephony devices designed for communications over a telephone network, may roam among various networks of each type of technology. If a wireless telephony device roams to an area covered by the packet switching network, it converts protocols to operate as a data device. If a wireless data device roams to a telephony network, it also changes mode. Means are provided to inform the home network of the wireless data device or cell phone that the device or cell phone has roamed onto a different type of network.