| 摘要 |
An underground communication system for providing communication between miners (58, 60, 62, 64) situated in stopes (50, 52, 54, 56) radiating from a mine adit (48), and a remote location (65). Each miner is provided with a light source, such as a miner's lamp, with which an optical user signal (72, 74, 76,78) with a predetermined characteristic or modulation is generatable. Relay stations (66, 68, 70) situated in the adit (48) outside the stopes (50, 52, 54, 56) receive a user signal from one of the light sources and transmit a relay signal (80, 82, 83) directly or indirectly to the remote location (65). Each relay station (66, 68, 70) preferably adds its own unique identification code to the relay signal (80, 82, 83) and includes means to suppress retransmission of a relay signal including that code and also includes means to transmit a confirmation signal to the miner upon receipt of either a user signal with the required characteristic or a return signal generated at the remote location. |
