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　　用于消防排煙系統中，當有火警發生時可通過該按鈕來緊急開窗排煙。緊急按鈕線路在遇到開路或者短路故障，排煙窗會立即自動開啟，保障了消防排煙窗系統的可靠性。

Used insmoke exhaust system, to open window and exhaust smoke by manual emergencybutton when firing, smoking window will open automatically when there is somewrong with open circuit or short circuit of emergency button line, Guaranteethe high performance of smoke exhaust system.