"alan kearn" wrote
| The sensors are wireless. The alarm bell box on the outside wall is
| connected to the control panel via a 4 ply wire cable. The power is
| supplied by 240 volts ac to a transformer that changes it to 12 volts
| dc. Hence the system is run on 12 volts dc. I will make the question
| easy, do wired alarms have a 12 volt back up battery
| if so I will be able connect the alarm bell box that is already fitted
| to the outside wall to the new control panel.
Err, well, that depends. There are several different ways of wiring an
external bell box. As well as the sounder wires itself there are anti-tamper
connections, which inform the panel if the sounder has been tampered with;
hold-off connections, the absence of which triggers the sounder if the cable
has been cut; and arrangements for charging the battery inside the sounder
which is used to power the sounder if the cable is cut.
Especially for a consumer-grade packaged system, those connections might be
proprietary or simply not supported, but might be required by a new panel.
By the time you've figured out what the old system did you might be as well
buying a new bell box that you know is compatible with your new panel.