Security & Fire Protection Systems/No alarm but intrusion detected


We inherited an ADT Safewatch Plus RF system with our house. It is not monitored.

Recently, we were away and armed it to "away."
When we returned, we listened for an alarm before opening the door and there was none. When the door was opened, there were the typical quick beeps while the system was disarmed. An intrusion was reported on one of the window sensors.
Does the intrusion alarm only sound for a certain length of time? How long does it go off?
Unfortunately, we cannot presume a false alarm because of present circumstances.

Hello Marie, and thanks for your question.

Yes, in most cases alarm systems have a timed-cut-off for the bell or siren. In many jurisdictions, this is a legal requirement (noise ordinances).

In general, the bell or siren is cut off after 5 minutes.

In addition, almost every control is equipped with a programmable feature called "automatic restore." What this means is that at the end of the five-minutes after an alarm is initiated, and if the faulted zone has returned to normal, then not only will the siren turn off, but the alarm system will be reset. In this case, another violation of a zone would produce a second alarm, and so on.

Since your system is not monitored, you won't be able to tell when the alarm occurred, or if there was more than one.

I hope this helps, and if you have additional questions, just drop me another note.

Best Regards,


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Dave Neuweiler


The design and application of burglary and fire systems for homes and businesses. Helping alarm owners understand how their system works. Helping to troubleshoot false alarm problems. Questions about monitoring issues.


Over a quarter century in the industry. Experience in installation, service, and monitoring centers. Training manager for a national protective services company; director of education and training for a national trade organization for for alarm dealers.


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