From what I gather, he already has this part working: motion on a camera triggers an output relay on the box to turn on the sirens. His problem is that he only wants it to work during certain hours, and the DVR doesn't have the ability to set a schedule for the alarm trigger; it's active all the time.
that's all correct, can you tell if i don't get it working by software some good digital on/off current shutter or whats it called?