Moved into a unit that has Fios home phone with currently no backup if power goes off. The box is located in a really bad inaccessible place. Can I install the 12-D cell unit and leave it switched on? Will it draw from the batteries even if the terminal is plugged in and electricity is OK?
What have others done? I just want to set it and forget it. The onus is on the user to make it available in case of emergency. How have others done their backup?