The bell box will have its own backup battery which you will need to disable by disconnecting or removing a jumper plug. I cant give you specific details as I dont know which bell box you have.
Before you disconnect bell box you should disconnect mains power and battery from the control panel.
make a note of where your wires are disconnected in the bell box. A point to note, if the bell box has a strobe, beware of high voltages to the strobe lamp and its circuits.
Pete, May 2007