| 摘要 |
PURPOSE:To ensure the data transmission in required minimum quantity even during communication, by controlling a transmitter so as to be switched for the data transmission using a sub-modulator by a communication confirming response or a communication request from an opposite station. CONSTITUTION:When a communication request switch 14 is depressed, it is confirmed at a communication control section 11, a sub-modulation section 2M is turned on, and the communication request signal is transmitted to the opposite station. In receiving the carrier at the opposite station, a carrier detecting signal CD is outputted from a sub-modulation section 2D. Further, when the signal CD is set, a signal RS to the sub-demodulation 2M is set as the confirming response to the communication request and the carrier is outputted. On the other hand, whether or not the signal CD is set is checked at the own station side and when the signal CD is set within a prescribed time, a display lamp 16 is lighted by assuming as a communication channel is established and a contact 7a is selected to a telephone set 5. Thus, the communication is made possible between both stations via a common line 20. |
