PURPOSE: To simultaneously transmit an acoustic signal from a master device to plural slave devices at the time of calling the plural slave devices from the master device.
CONSTITUTION: A master device 2 is equipped with a telephone set circuit(TELNW) 21, radio transmitting part (TX) 22, radio receiving part (RX) 23, microphone 25, calling control button 26, and acoustic signal detector 27. When the operation of the calling control button 26, or the detection of the acoustic signal from a telephone line 1 by the acoustic signal detector 27 is transmitted to a control part (CONT) 24, a slave device 3 is called through the TX22 by the control of the CONT 24. When a response is transmitted from the salve device 3, the acoustic signal can be transmitted from the microphone 25 or the TELNW 21 through the TX22 to the slave device 3. The slave device 3 is equipped with a radio receiving part (RX) 32, radio transmitting part (TX) 33, sounder 35, and speaker 35. Then, an audible display or the like at the time of an incoming call is operated by the sounder 36, and the acoustic signal from the master device 2 is transmitted through the RX32 from the speaker 35.
SHIMURA YUKIHIRO
NISHIMURA NAOYASU
ADACHI KOICHI
NIPPON TELEGRAPH & TELEPHONE
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