PURPOSE: To perform instruction and mutual communication effectively by connecting a coupler to the high-frequency induction line in the drift and multiple-using a frequency, which is used in one high-frequency induction line, as different values in the mutual communication between workers.
CONSTITUTION: High-frequency induction line 3 where matching resistor 2 is inserted is arranged along side wall A' of drift A, and monitor TV 4 installed in direction room B and wireless telephone set 4' are connected. Further, wireless telephone set 4' in anteroom C, voice receiver 12 connected to demodulator 13, wireless telephone sets 11 and 11' provided in required positions in drift A", TV camera 8 and modulator 9 are connected to high-frequency induction line 3. Then, the antenna of transceiver 15 and the connection between high-frequency induction lines 3 for machines in drift A' and anteroom C are connected through antenna 10, and a frequency which is used by one high-frequency induction line 3 is utilized as different values, and the interference of instructions and mutual communication is avoided to mutiple-utilize the frequency.
SUETSUGU SHIYUNSUKE
NAKAMURA YOUICHI
KODAMA FUJIO
NINOMIYA TSUKASA
