Abstract: A communication apparatus comprises a destination obtainer that obtains a destination address, a telephone network interface that connects to a public switched telephone network and a LAN interface that connects to an Internet. Further the communication apparatus includes a communication controller, an Internet communication controller and a network communication controller. The communication controller analyzes the destination address obtained by the obtainer to determine whether communication is performed via the telephone network interface or via the LAN interface. The Internet communication controller performs voice transmission over the Internet via the LAN interface when the communication controller determines that the communication is performed via the LAN interface and the network communication controller performs voice transmission over the public switched telephone network via said telephone network interface.