声报警器 meaning in English

acoustic alarm
acoustical alarm

There are a lot of ways to realize the alarm when the train approach , and sound alarm is used in this device , when the sensor receives the train - approaching signal , the controller will analyze and handle the signal of coming train by the direction of coming train , and make an alarm signal of up or down traveling train approaching
列车接近报警的实现有很多方法，本仪器采用声报警器的工作方式，传感器接受到列车接近信号，控制器对来车信号进行分析处理,并按来车方向，通过声报警装置发出上行或下行列车接近报警信号。