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Author Topic: Window/door sensor compromised?  (Read 6287 times)

cscjjd

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Window/door sensor compromised?
« on: May 24, 2011, 09:26:46 PM »

Hi,  I am new to X10 and forum...

My question is: Assume the alarm is armed but an intruder breaks the window glass and reaches in and removes the
wires from the magnetic switch (without moving the window or switch).  Has the intruder defeated this part of the security system or will the SC1200 dial the phone and sound the alarm when wires are removed?

Thanks for your patience,

JD
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dave w

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Re: Window/door sensor compromised?
« Reply #1 on: May 24, 2011, 09:32:43 PM »

The window switch is a "normally closed" connection.   i.e. a closed loop. Meaning, if the switch gets disconnected, wire is cut, etc. the alarm is triggered.
« Last Edit: May 24, 2011, 09:34:29 PM by dave w »
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cscjjd

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Re: Window/door sensor compromised?
« Reply #2 on: May 24, 2011, 09:41:46 PM »

Will it also go off if the intruder removes the batteries?  (I'm curious because I saw some instructions that said to hide the sensor behind a curtain so that an intruder would not see it)
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Brian H

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Re: Window/door sensor compromised?
« Reply #3 on: May 25, 2011, 06:05:15 AM »

If the kit came with the DS10A. Removing the batteries would disable it, but you would have to do it before the zone was violated.
DS10A is the one with the externally connected magnetic switch. I believe what is now in presently selling kits.
http://kbase.x10.com/wiki/Security_Door/Window_Sensor

If the kit came with the DS12A. It has a built in tamper switch. Try and remove the cover. It sends a tamper signal to the SC1200A.
DS12A is smaller and has an internal magnetic switch. With the magnet and sensor mounted next to each other when installed.
Also has a set of terminals in it to connect an external magnetic switch. That is a second separate zone from the internal one.
http://kbase.x10.com/wiki/DS12A
« Last Edit: May 25, 2011, 06:55:41 AM by Brian H »
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cscjjd

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Re: Window/door sensor compromised?
« Reply #4 on: May 27, 2011, 12:27:23 PM »

Just to be sure that I understand correctly (from Dave's and Brian's answers)... 
using the DS-10A window/door sensor with the alarm armed,
 
if the bad guy cuts or pulls the wires out the alarm will sound and phone out etc.

but if the bad guy removes the batteries, nothing will happen and this particular zone has been compromised.

Correct?

Thanks,

JD
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Brian H

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Re: Window/door sensor compromised?
« Reply #5 on: May 27, 2011, 12:32:27 PM »

Sounds correct.

Though I have never had a DS10A to try removing the batteries from for results.
I doubt the electronics have enough power supply capacitors to send any messages with no batteries.
Now if they where removed for a future break in. In four hours of not reporting in. A problem zone would be flagged.
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dave w

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Re: Window/door sensor compromised?
« Reply #6 on: May 27, 2011, 01:25:20 PM »

but if the bad guy removes the batteries, nothing will happen and this particular zone has been compromised.
I agree with Brian, it sounds right.

Are you concerned about this? Because it is not unique to X10. My point is your questions are universal, and you will probably get similar answers when applied to any other alarm system.

If your concern is breaking the glass and removing the batteries, a fix could be adding a glass break sensor to the window switch loop.

The "cheap' version is a mercury switch stuck to the glass. The idea being when the glass breaks the mercury switch "tilts" and opens the circuit, triggering the alarm.

The high tech version is a self contained battery powered device that is sensitive "to the sound of breaking glass". When detected the device opens the window switch circuit which triggers the alarm.

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cscjjd

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Re: Window/door sensor compromised?
« Reply #7 on: May 27, 2011, 02:19:10 PM »

Thanks guys (Dave and Brian) for sharing your knowledge. 
This will help me in planning where to locate each of the switches for maximum security.
JD
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Brian H

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Re: Window/door sensor compromised?
« Reply #8 on: May 27, 2011, 03:10:47 PM »

If you like stringing wire loops. The SC1200 has two hard wired zone inputs for NC {Closed when not violated} style contacts.
« Last Edit: May 27, 2011, 03:15:25 PM by Brian H »
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dave w

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Re: Window/door sensor compromised?
« Reply #9 on: May 27, 2011, 08:58:16 PM »

Long time ago I put foil alarm tape on all the windows for an alarm system. Worked great until the cat, probably batting a fly on the window, scratched through the tape. Was not a good day. Have not used foil since. It is ugly, but probably one of the best glass break detectors.
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