Abstract: A communication apparatus is provided between the first communication network to which a portable terminal is connected and the second communication network having a communication protocol different from that of the first communication network. This apparatus includes a 3G gateway and DTMF detection unit. The 3G gateway performs communication protocol conversion between the first communication network and the second communication network. The DTMF detection unit detects a control signal contained in voice information from the portable terminal. An operation control method for a communication apparatus is also disclosed.

Abstract: Each of control signal transmitters (21-2n) is provided for each of a plurality of guide objects and transmits a control signal for discrimination of the corresponding guide object. A control signal detector (13) starts execution thereof by operation of a start button (12). A control signal detector receives the control signals, each of which is supplied from the control signal transmitters and detects one of the control signals, which has the maximum level for use of selection of one kind of the voice-data corresponding to the detected control signal transmitter. A controller (14) has received a message class such as a language class of Japanese or English for example from a class selector (19). The controller makes and sends out a selection signal with a detected control signal and a selected language class to a voice-data take-out circuit (15).