Bell box wiring insecure??

[squowse]

I am renewing the alarm panel with a texecom premier elite 24 and a few new sensors.
I've learnt about how to do the FSL - two resistor wiring so that the sensors cannot be shorted out and disabled.
I am concerned about the bell box though. It's a standard 5 wire one.

If a burglar was to access the panel for example and connect the "Bell -" wire to 12v I think the bell would stop?

Or if the cable was intercepted and Bell- wire connected to the 12v wire?

This seems too easy.

I see in the texecom manual their own bells have a few more connections. Is this to avoid the above problem and make them more secure in a similar way to the FSL wiring eg using various resistances that would be hard/impossible to mimic by tampering?

 

[pcaouolte]

The panel should be within the protected area so that the burglar cannot get to it without setting off the alarm.

If the burglar opens the panel when the system is set the sounder will sound due to the panel tamper.

If the burglar can open the panel and knows how alarms work then he can silence the sounder however it is connected.

If the bell wire is "intercepted" the burglar does not know which wire performs which function. The bell wire should not be exposed outside the protected area.

Burglars usually want to steal things and make their escape quite quickly, not play at being alarm engineers.

The extra connections in some Texecom sounders are to monitor the sounder battery status, the supply voltage and the integrity of the trigger wire, they also allow remote testing of the sounder. They won't prevent a burglar who has internal access to the panel from silencing the sounder.

 

[squowse]

No problem with all of the above, i understand.
Whilst looking for some instructions for something else I came across this -
http://www.cqr.co.uk/technical-support/bellbox-faqs
these bell boxes seem to be similar to the FSL wiring - they require resistors in the control panel. I suppose it would still be possible to insert links to silence the bell once the panel was open.

 

[pcaouolte]

The sounders in your link monitor the trigger wire using resistors. Texecom sounders (not the E range) monitor the trigger wire using the extra connections mentioned in your original post. These systems can still be defeated if the burglar can get into the panel without setting off the alarm.

If the burglar can get the panel open without setting off the alarm then the alarm was not designed or installed correctly or is not being used correctly.

There are easier ways for a burglar to disable a sounder without the need for him to get to the panel or cables. I'm not going into those methods on here.

If you are concerned about a burglar disabling the sounder consider a monitored alarm or an auto dialler so that you can still be alerted if the sounder is defeated.

Keep in mind that a burglar has little knowledge of your system, how it works or what facilities it has. Most will just see the sounder and try elsewhere.

 

[squowse]

yes i was thinking more about the situation where the alarm is going off but the bell can be silenced by access to the panel or wiring.

 

[scott1980]

I think the chances of this happening in reality are quite remote! A burglar is more likely to simply smash the control panel off the wall. They're not going to turn up equipped with a 3mm terminal driver!

There are quite a few bell boxes on the market today that utilise "trigger wire monitoring". This involves installing resistors in the bell box and causes it to sound if the trigger wire is disconnected or damaged. CQR are a manufacturer of such units.

 

[squowse]

yes that's what i'm talking about - if the burglar smashes the panel off the wall the bell will continue to sound.

anyway i'm just looking at it technically not weighing up the likely behaviour of burglars. i don't suppose they'll put the kettle on, and have a cup of tea whilst checking out the wiring either.

as I see it in the sensor wiring the tamper loop protects against the cable being cut. and in fsl wiring additionally the eol resistors protect against the cable being "hot wired" ie the correct 2 wires being shorted together. again it's highly unlikely someone would be able to pull this off without a) triggering the alarm before getting access to the wires or b) picking the wrong 2 wires and setting off the alarm. Once the alarm is set off then game over.

the sensors are all protected both ways - but it seems to me that the sounder is only protected against a wire cut with the standard wiring.
and it is possible to silence it after an alarm trigger.

I do have a GSM unit and all the bellbox wiring is inside the house. As I say I'm just thinking it through logically. I thought there might be an answer how it wasn't possible and I would learn something.

 

[Europlex]

My mistake