信号灯受一个启动开关控制，当启动开关接通时，系统开始正常工作，且先南北红灯亮，东西绿灯亮；当启动开关断开时，所有信号灯熄灭；南北绿灯和东西绿灯不能同时亮，如果同时亮则应报警后关闭信号灯系统。-To start signal by a switch control, when the start switch connected to the system started to work, and the first north-south red light, green things　when the start switch off all lights extinguished　north-south and east-west green light green light can not be at the same time, if At the same time, bright lights should be shut down after alarm system.