What type of alarm controller can be connected to an 'VE?

Question

I have set up the camera system and on the back of the NVR has digital I/O ports . I want to siren and strobe to come on when the alarm is triggered by motion during the set hours which are programmable through the NVR interface. I don't have any knowledge on the alarm side of things what can I connect there to obtain desired results should I be looking elsewhere or at other devices like smartphones instead not wanting to spend too much more on this project