When a call-up is generated, an data type identifying unit of a CPU identifies the type of data type information which is appended as a header to received data as one of sound data, text data, and image and sound data, and displays the type on a display unit comprising a monitor. When the type is sound data or text data, an application for executing a corresponding telephone function or data communication function is activated via the user line connection. When the type is image and sound data, an application for executing a corresponding visual telephone function is activated after line connection.