the first place to look is in the owner's manual. If you don't have one, you can find a virtual copy at MyADT.com. The manual will also explain how to silence the low battery alarm. Depending on the model, you may have to: ...
continuous beeping and the word "check" on your security screen. This is annoying and may cause you to want to reset your ADT alarm system, but it's meant to get your attention