1. Yes, the buttons are powered by CR2032 batteries, and when the button is pressed an LED lights to let you know it worked. (i.e. You can detect when they're

1. Yes, the buttons are powered by CR2032 batteries, and when the button is pressed an LED lights to let you know it worked. (i.e. You can detect when they're empty.) My batteries have lasted for several months so far, but I don't know how long to expect them to work. 2. Not sure what you're getting at here; anybody "local" could probably overhear the transmission. And probably perform a replay attack. 3. There is no feedback on the buttons, you press the button and they send a radio transmission (+ light the LED). There is no facility for two-way communication. If I were building the buttons myself I'd probably have them both send and receive, such that you could use an ACK system. But the whole point is to use cheap & off-the-shelf parts so ..