Yes, you can activate anything you like such as a security light to a door lock release - anything that requires a voltage free trigger can this system activate, it could even activate your house alarm (Assuming your house alarm has voltage free inputs)
Why are there 4 buttons on the key fob?
It depends upon how you set the internal jumper links inside the main DA2800 unit, but each button will activate one of the 3 outputs provided
I have a remote key fob for my driveway gates, and a remote key fob for my garage, could I use this system to operate both?
Yes you can
How easy is it to program key fobs?
Simple and less than 15 seconds to complete
Can I have extra keyfobs?
Yes, you can program a maximum of 40 keyfobs to the unit