None.  The best part about owning the SC-1000 is that it is a self-monitoring center on its own.  In the event of an emergency all monitoring companies do is make the call to the emergency services for you.  The SC-1000 comes with an emergency phone dialer which in the event of an emergency will call up to 9 different numbers, and sends your personal, (up to 40 second long) recorded message to the person of your choice, thus, eliminating the need for a monitoring company and the costly monitoring fees.