Nextalarm is a flat fee service. It doesn't matter how many switches or motion detectors or smoke alarms you have, the monthly fee is the same. If an alarm goes off the panel reports to the central station by telephone line, cable modem, or VOIP, the zone and type of alarm. The Central Station will then do whatever you have told them to do, i.e. call the police, fire, cousin Sal, call you on your cell phone, or do nothing. They will also monitor a cellular backup for an additional $7.50 per month.