There are predominantly two types of security systems.
An 'AudibleOnly' security system has external/internal sirens as well as an external strobe light. In the event of an alarm event the sirens and strobe light will activate but does not send a signal to a control room. Therefore, it is not possible to have anyone attend to the break-in unless a third party nearby hears the alarm and actions it.
Also, there are no capabilities to eliminate human error in remembering to switch the alarm on or to determine who switched the alarm on or off and at what time etc.
Control Room Monitored
A 'Control Room Monitored' security system also has the capability to have sirens & strobe lights connected plus much more. This is by far the most commonly used system due to its secure level of communication to the control room.
Any alarm events will be descriptively communicated to the control room by the alarm panel dialler. A control room can identify which of the system users (staff) entered/exited premises and at what time. They can also determine where alarm events have been generated and the amount of activations.
System faults like AC fail, low battery and communication failure are also sent to the control room and recorded. When a control room receives an alarm event an operator will follow the client’s requests (i.e. send a patrolman or contact after hours recalls). When a security system is control room monitored a premises refrigeration alarms can also be incorporated into the alarm system.