| 摘要 |
PURPOSE:To prevent echo by using a prescribed calling code to attain the assignment of a selective calling number to each receiving slave station. CONSTITUTION:A transmission signal from a master station 1 is received by receiving stations 3, 6 and 9 in the same area and a prescribed broadcast is attained by trumpet speakers 5, 8 and 11. Selective calling codes 21, 23 and 24 of a transmitted signal from the master station 1 consist of the combination of plural codes, the same contents are broadcast continuously for twice or over, and a part of order of arrangement and code length in the plural codes are changed at each calling and transmitted. Further, each receiving station receives selectively only one of the selecting calling code changed in the order of arrangement and code length and outputted with a loudspeaker. |
