用继电器操作的一种可视信号或音响信号装置，用以指示有关电路的情况。
A visual or audible signaling device, operated by relays, which indicates conditions of associated circuits.
在城市主干道约500个红绿灯路口安装了盲人过街音响信号装置，350个路口安装了行人灯绿闪倒计时器。
All of them are paved with blind paths and stone ramps. 500 main intersections are installed with sound devices to guide the blinds. 350 intersections are installed with green light count down device.
在城市主干道约500个红绿灯路口安装了盲人过街音响信号装置，350个路口安装了行人灯绿闪倒计时器。
All of them are paved with blind paths and stone ramps. 500 main intersections are installed with sound devices to guide the blinds. 350 intersections are installed with green light count down device.
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