Recordable voice sirens are one of my favorites. The Elk 120 is a little pricey, but you can do some neat stuff with it with its 4 voice channels and
4 inputs. I have one at a school that blasts a message throughout the building whenever anybody arms the alarm as a warning. It has a different message that plays through out whenever somebody enters the building as well. Of course it has the typical "burglary burglary burglary" message that plays when the alarm goes off as well.Since I set it up they have not had a single entry or exit error.
"The alarm has been activated. Exit the building immediatley. If you need to stay in the building contact somebody with a valid alarm code and disarm the alarm" or something like that.
"The alarm system is active. You must disarm now."
I have another application where a business has deliveries dropped off in lockable containers in their side yard. The carrier puts the delivery in the container and then locks the container. This requires them to leave a side gate unlocked. We set up an armored contact on the gate. It trips a trigger output on their alarm that plays a custom message. "Delivery drivers ONLY beyond this point. ALL OTHERS ARE TRESSPASSING. You are being video taped. Tresspassers will be prosecuted." Then we set the alarm up to page the business owner whenever the gate is opened. It is a great stop gap. System. We also use the trigger output to trip a relay which activates the alarm input on their digital video recorder to switch that camera to real time whenever that gate is opened. Made for an interesting interaction when a delivery driver tried to lie about making a delivery.
"Golly, there is no video of you in that area, and gee... you never opened the gate. Maybe you should double check your truck."
Bob La Londe