Burglar alarm signals for a home security company

Your company monitors burglar alarms in 60,000 homes. When an alarm goes off, the home's alarm panel sends a signal to your monitoring center. An operator sees it on screen, calls the owner and sends a guard or the police. Your team writes the software in the panels and in the center.

Today a panel sends each signal once, over the home's internet, to the center's one receiver server. Each signal carries the panel's ID and a number the panel gives each alarm. Last month a burglar cut a home's internet cable before breaking in, and no signal arrived. 2 weeks later the receiver server crashed and was down for 40 minutes.

Each panel also has a cellular modem, with a data plan of 5 MB a month. A signal is about 200 bytes. It must reach an operator's screen within 30 seconds of the alarm. On a stormy night, up to 3,000 alarms can go off in an hour. Operators should see each alarm once.

When an alarm goes off, what does the panel do, and what does the center do with each signal that arrives?