Within each category of alarm (wired or wireless) there are two further types of system:
- Audible-only system
- Remotely monitored system
An audible-only alarm operates by sounding a siren or bell when the alarm is activated, and relies on the noise the alarm makes to deter burglars and alert owners to the fact that a robbery is being attempted.
Remotely monitored systems can be audible or silent, but are connected to the outside world via a phone line. This is predominantly achieved through a GSM unit (using a GPRS mobile network) or landline. They send a signal to an alarm receiving centre (ARC) which informs you or a nominated keyholder(s) and/or the Gardaí (once verified – activation of at least two devices) that the alarm has been activated.