To clear a FC on an alarm system that is not monitored by a professional company you will need to:
1.) Enter programming. Do this by entering 4112 800. The Screen will show "Installer code 20" (on an Alpha Keypad. It will show just a "20" on a Non-programming keypad, also known as a Fixed English Keypad)
2.) Now we need to clear out any programming that is telling the system to "Communicate out". Do this by entering: *41*, *42*, *43*, *44*, *99. This will return you to normal mode and you will no longer have a FC or communication failure.