Have intercom with relay hooked up to ELK. What is stopping someone from manually jumping the relay?
- Thread starter ghurty
- Start date
tmbrown97
Senior Member
OK all the references to the RTFM button were mildly amusing...
That unit claims to have an intrusion sensor - an optical sensor that will be activated when the intercom is removed from the case.
So - if it were me, after about 30 seconds of thought, what I would do is wire both the relay and the intrusion sensor into input zones on the Elk, and absolutely don't have any direct ability to control the door via the onboard relay. Then you could set the intrusion sensor for 24-hour tamper and have instant alarm/notification if anyone pulls it off the wall.
Along with that, you could set some rules such that, if the intrusion sensor is activated, it either disables the door via an output, or by bypassing the intercom zone; rules for the intercom zone could be set to not fire if the output flag is set from a tamper, or if the alarm is in any state, etc.
You could probably do something with 4-state wiring and all that, but that wouldn't set a persistent state should someone open the box, attach some leads, then close it (turning off the intrusion detection) then making the contact. Of course you'd have the instant alarm from tamper, but I'd like aa more active disabling of the intercom contact.
That unit claims to have an intrusion sensor - an optical sensor that will be activated when the intercom is removed from the case.
So - if it were me, after about 30 seconds of thought, what I would do is wire both the relay and the intrusion sensor into input zones on the Elk, and absolutely don't have any direct ability to control the door via the onboard relay. Then you could set the intrusion sensor for 24-hour tamper and have instant alarm/notification if anyone pulls it off the wall.
Along with that, you could set some rules such that, if the intrusion sensor is activated, it either disables the door via an output, or by bypassing the intercom zone; rules for the intercom zone could be set to not fire if the output flag is set from a tamper, or if the alarm is in any state, etc.
You could probably do something with 4-state wiring and all that, but that wouldn't set a persistent state should someone open the box, attach some leads, then close it (turning off the intrusion detection) then making the contact. Of course you'd have the instant alarm from tamper, but I'd like aa more active disabling of the intercom contact.
That documentation is horrible.
I think that a set of tamper resistant screws on a unit installed into a 2 gang bell box isn't likely to be opened or pulled off the wall too easily, however the way to do it would be to have 0 control or connections from the unit to the Elk and do everything inside via the SIP
I think that a set of tamper resistant screws on a unit installed into a 2 gang bell box isn't likely to be opened or pulled off the wall too easily, however the way to do it would be to have 0 control or connections from the unit to the Elk and do everything inside via the SIP
tmbrown97
Senior Member
I was pretty surprised to see that it didn't even come with tamper-resistant screws - just a regular phillips?
What would be the interface from the SIP device back to the Elk or the door control? None come to mind off-hand.
What would be the disadvantage to what I proposed above? If the thing comes off the wall it triggers a tamper switch setting off an alarm and disabling the door trigger - seems pretty safe to me. If you're worried about someone using those wires to short out the elk, you could use an interim set of relays or some opto-isolated contacts - but that's pretty extreme.
What would be the interface from the SIP device back to the Elk or the door control? None come to mind off-hand.
What would be the disadvantage to what I proposed above? If the thing comes off the wall it triggers a tamper switch setting off an alarm and disabling the door trigger - seems pretty safe to me. If you're worried about someone using those wires to short out the elk, you could use an interim set of relays or some opto-isolated contacts - but that's pretty extreme.
wkearney99
Senior Member
Don't ignore the fact that someone breaking in is a lot more likely to go low-tech anyway. As in, just kick in the door or break a window. Somestimes you just chase your tail trying to prevent the 'possible' while ignoring what's a lot more likely.
