The use of Wi-Fi enabled cell phones to access internet away from the PC is increasing day-by-day. The use of Wi-Fi enabled phones as IP phones, and their communication within a local wireless LAN is discussed in this paper. This proposed model is a form of telecommunication that allows data and voice transmissions to be sent across a wide range of interconnected networks. The models, which are Wi-Fi enabled and have J2ME platform, can be used to communicate with each other through the free 2.4GHz communication channel. Since this is a free channel, security is a priority. In order to engender security, the packets of data may be encrypted in the header and payload by different encryption techniques. However even the security is a concern only within the specific network, the communication is completely safe from attacks external to this local network. Each mobile device connects to a WLAN router and identifies itself in the routing table. Calls can be placed by a user by sending the packets to the router, which then tries to find the destination. The destination must also be connected to the WLAN; if not the Wi-Fi server can tunnel the calls to the GSM network using UNC (Unified Mobile Access Network Converter). Since the communication channel is only capable of being affected by an inside influence (hacking), it is provided with complex cryptography techniques, which engenders high security. Our proposal allows free calls within the network with high quality voice transmission. This model will be a prototype of itinerant devices communicating through in the Wi-Fi bandwidth and will greatly reduce the communication cost in large organizations.
