The blinking red light on a First Alert SC9120B/FF means the alarm needs to be reset by pressing the Test/Silence button. The green light means there is AC Power connected to the alarm.
I am surprised that the red light on the alarm was in sync with the music! Try it! Listen for the bell and look at the light.
This video was not recorded at my house. It was recorded at another family member’s house. If you want to see my home alarms, then go to this video, and tap my channel icon, and you will see all my other YouTube Shorts, then select the video named “My alarms in my household!”
