A cost-effective system and method of sending and receiving high quality phone calls over a low-cost network (e.g., a local area network, a WiFi network, etc.) with a wireless device, where such phone calls would typically have been delivered over a cellular network to the wireless device is provided herein. The system enables the wireless device to retain a phone number assigned by its home cellular network to send and receive calls, while still sending and receiving such calls over the low-cost network. The system also enables wireless devices to be authenticated with the home network of the wireless device for purposes other than sending and receiving high-quality phone calls.