You can try ADT. Once the power is cut, it will send a singal using its 8hrs long backup batt in the unit to the monitoring station. In no time you will get an security representative calling you regarding power failure which might indicate burglary in your house ..kee..kee..
On other note, you can even call back your system and say hello to your fishes thru the intercom system and also hear the background sound of water dripping out of your tank