Hit the "Reset" button on the control panel if the system is malfunctioning. A system reset will often take care of any temporary glitches in the Brink's system.
Check all your doors and windows to ensure they all close properly and that the sensors attached to them are working properly. If a sensor is loose, it could result in sporadic false alarms. The magnet should match up exactly with the contact, because a misalignment could cause alarm activation.
Move any glass-break sensors away from vents, ducts or doorbells. They are activated sonically, meaning a sound of a particular pitch will set them off. Loud pets could also cause a false alarm in this circumstance.
Check your motion sensors to verify that they are not aimed directly at windows or light sources, since the light variance could result in alarms. Position wide-lens sensors about 7 feet off the ground.
Examine any other control panels in the home. If only one panel is showing an error, that panel may be faulty and may require replacement.
Disconnect the main panel if your phones are not working properly to see if the panel is interfering with phone service. Call your monitoring company if the panel is disrupting phone service, since it will require repair or replacement.