Elk M1 RS-485 data bus


Active Member
I finally ordered my M1 Gold and I'm currently planning the wiring of the sensors and LCD panel. The most aesthetic patch for wiring the LCD panel near to the entry door would route it inside my garage, which is not very secure.

What if somebody enters the garage and tampers with the data bus cable, would the controller notice it? Would it trigger an alarm? If not, I would have to contract and electrician to install metal pipes to protect the cable.
It would detect the senors but not the Keypad. I beleave if the RS-485 line is cut it would take down the rest of the RS-485 devices on the RS-485 network. It is always better to mount the Keypad inside the door going into the house.
I haven't finished install of my Elk, but on my Napco, if the RS485 line was dropped, the panel would notice that a keypad went offline and would sound an alert. The Napco keypads are also bugged so that if you attempt to remove the faceplate there is an internal switch that triggers sounding alarm.

I assume that the Elk does similar, but will know for sure later this weekend when I get mine going :lol:
When any device on the data bus goes missing, there is an alert and an event is fired which can be used in a rule to turn on the siren.

Another idea is to run one of the zones in the extra pair of Cat 5 cable. If anyone cuts the wire the zone will trigger and call the central station and turn on the siren. Since negative is common on one side of every zone input, you only need one wire to run back to the zone input.
That's a great idea Spanky.

I plan to have a similar situation, but since the doors (regular and garage door) plus the window will be alarmed I was not too worried as they would have had to trip one of the other zones to get to that point (until I bury the wiring further).

Adding Spanky's idea to it should cover it even further.
One more thing on a missing zone expander. On the M1 or EZ8, if a zone expander is removed and the burglar system is armed, and zones are programmed as burglar on the expander, you will get a burglar alarm indicating all the missing zones. This will take several seconds after the expander becomes missing due to a verification routine to insure the expander is missing and it is not data bus noise.