How an ADT Security System Works

First in brief what is security system and what elements it consist of. 

Security system is a combination of electronic devices that sets of an alarm when certain conditions occur. Security system could be hardwired, where all devices connected using wires, Wireless – communication between devises with Radio frequency waves or Hybrid – which utilize both technologies.

Every security system has:

• Control panel - the hard of the system, were we can find the main processor programmed to analyze signals coming from devises and respond promptly and were usually back-up battery and telephone communicator located
• Key pad  - from were you control your alarm and see status of the system. Some of systems (especially wireless) have control panel integrated in to key pad.
• Siren – loud sound device to notify people on premise and neighbors that alarm occurs. 
• Censors – device which reports to control panel of changes in conditions it set for. There are some sensors which could be used in security system and their definitions:

Door/window contact – protects perimeter of a premise, signal to control panel if door/window closed or open.
Motion detector - protects interior of a premise, signal to control panel if there is a movement inside the premise detected.
Glass break detector – detects a sound of a broken glass
Smoke detector – detects smoke in event of fire at premise
CO detector – detects higher then normal level of “silent killer” Carbon monoxide at premise.
Flood detector – detects and report rising water in protected area.
Low temperature detector – detects drop down from preset temperature value in case of premise heater break down.
High temperature detector – detects and report rising from preset temperature value.
Panic/emergency button – push or hold-up button activated by person in event of emergency ( police, medical, fire), usually located on key pad or could be installed in separate location.
 

How it works

Every modern security system installed protecting determined zones in a premise. Zone usually represents one or more sensors installed in a certain location of the premise. For example: zone 1 - front door, 2 – hall motion detector, 3 – smoke detector, 4 – basement windows.

Some of the zones, like smoke detector, panic button, active all the time, but most of them active only when system is ON.
All systems have options to put system ON – ARM in different modes, there are some of them:

AWAY – arming all zones – usually used when everybody out of premise.

STAY – arming all zones except motion detectors – used when somebody stays inside, so only perimeter of premise protected.
In some systems we can use

NIGHT STAY – arming all perimeter zones and some motion detectors usually used at night, so the motion in a basement, for example, will be armed during the night but motion in hall off

Different types of systems have different ways of arming, most common armed by putting customer security code or just pressing STAY or AWAY buttons. When we ARM system we usually have EXIT DELAY – time after system will be armed, it is usually 30-90 seconds (programmed by installer). During this time system giving us time to leave the premise.

To DISARM system usually we need to put security code only, or security code and OFF button. There is always ENTRY DELAY to disarm system when come back – time sufficient to entry the code when you entry the premise. Some systems could be armed on INSTANT STAY, when there is no entry delay at all – it used usually at night when we know no one will come.

Now what happens when there is a break in?

When somebody got in the house one or more censors will activate alarm, siren will sound and system will send signal to the ADT monitoring station and operator will dispatch authorities right away and then notify owners what happened.