Outdoor Activation/Deactivation Of An Alarm Panel.

If you know how to connect a relay to an input of the alarm panel, you can connect the relay output of a receiver like this one to an input of your alarm panel programmed as a keyswitch input. You program the wireless receiver to toggle open/closed when you press one or more of the buttons of a wireless remote like this one.

You can have one button disarm and another arm or have the same button toggle open/closed on the relay. The receiver will work at up to 600 feet line of sight (maybe half or less of that distance if the receiver is installed inside of a garage) and you can have up to 600 remotes programmed into it in standalone mode

That would definitely work with a Vista 20.

It's too bad the Vista 20 doesn't support prox readers, then you could have used the receiver I mentioned above in wiegand mode and and been able to identify who was arming and disarming (same as with a card) using the remote

Thanks for the suggestion, Matt. May be worth looking at.

Based on lines of thought here and some more searching I also found this remote wireless keypad and receiver from Linear.

Some good leads to call on Monday. Thanks.