An alarm system is made up of different elements or electronic devices, which together are capable of detecting and recording events of an abnormal or risky situation and producing an alert signal to obtain an immediate emergency response. It is commonly known to be a passive safety component. This means that, although it cannot prevent an abnormal situation, it can prevent or reduce major risks by warning about them, serving as a deterrent against possible problems. For example:.

These systems can reduce the response time of the police and other emergency services, and facilitate the actions to be taken according to the problem presented, thus reducing losses.

Once the alarm starts working, or is activated depending on the system installed, it can send a telephone message to one or more numbers. The use of telephony to send messages of signals or events has been used for 60 years, but since 2005, with the digitization of telephone networks, communication is no longer secure. Currently, telephony is just another link and messages must be sent using GPRS to IP addresses of servers that act as receivers of signals or events. The connectivity of IP networks is also used.

If the presence of smoke, heat or carbon monoxide is detected, the system sends a message to the Alarm Receiving Center or activates the opening of sprinklers on the ceiling to put out the fire. If the presence of toxic agents is detected in an area, it can close the doors so that the problem does not spread.

There are two types of alarm systems:

One of the most widespread uses of an alarm system is to warn of a break-in in a home or premises. Alarm equipment can be connected to an Alarm Receiving Center (ARC) (also called Monitoring Center), to the owner himself (via telephone or TCP/IP) or simply fulfill the deterrent function, activating a local siren. Currently there are "Internet monitoring" services that do not use an Alarm Receiving Center, but rather use shared networks on the Internet where signals or events are directly derived to smartphones, tablets "Tablet (computer)") and laptops connected to the Internet using an open source browser (for example, Mozilla Firefox). These send the information directly to the users or owners of the services, to the technical staff for the repair of false alarms, to the monitoring operators who verify the signals that require human processing and/or to the application authority (police, firefighters, etc.) in the case of real events where the state must intervene.